Advanced stats like VO2 Max, or maximum oxygen intake during workouts with increasing intensity, are also nice to have, along with training assessments to keep your workload in check and make sure you're getting in effective aerobic and anaerobic workouts. It's also a plus when a watch also supports other sports, like cycling and swimming, which all of these do. As for features like smartphone notifications and NFC payments, those are nice bells and whistles, but not necessary, especially if they drive up the asking price.

Without further ado, I bring you capsule reviews of four running watches, each of which I ultimately recommend, none of which is perfect. And keep in mind, when it comes time to make a decision of your own, there are no wrong answers here: There are at least two watches on this list I like so much I switch back and forth between them in my own training.

Apple Watch Series 5

What you get: A jack-of-all-trades GPS watch that also happens to be our favorite smartwatch. Pros: Stylish design; a great all-around smartwatch you'll want to use even when you're not exercising; automatic workout detection; wrist-based heart-rate monitoring; support for lots of third-party health platforms; precise treadmill stats; heart health features are a nice bonus; optional LTE is nice to have. Cons: For iPhone users only; shorter battery life than the competition might concern endurance athletes; fewer performance metrics and settings than what you'd find on a purpose-built sports watch; distance and average pace readouts sometimes seem overly generous. Buy Apple Watch Series 5 at Amazon - $385+

Update (5/13/2020): We’ve changed our pick from the Apple Watch Series 4 to the Series 5 after reviewing the newest model.

Don't think of the Apple Watch as a running watch. Think of it as a smartwatch that happens to have a running mode. Nearly four years after the original Watch made its debut, Apple has successfully transformed its wearable from an overpriced curiosity to an actually useful companion device for the masses. But being a gadget for the masses means that when it comes to running, the Apple Watch has never been as specialized -- as feature rich -- as competing devices built specifically for that purpose.

Before I get to that, a few words on why I like it. I wear the Series 5 every day. It's the watch I want to wear when I'm not running. (And I sometimes wear it even when I am running.) It's stylish, or at least as stylish as a wrist-worn computer can be, and certainly more so than any running watch I've encountered. The aluminum, water-resistant body and neutral Sport band go with most outfits and still look fresh after nearly a year of sweaty workouts and untold jaunts through the rain. If money weren't an object, I'd spring for the stainless-steel version.

The battery life is long enough for everyday use. Apple claims 18 hours; for my part, I have no problems making it through a typical day. I can often put it back on after a night of forgetting to charge it and still have some juice left. That said, other running watches claim longer usage time -- between 30 and 40 hours in some cases. When it comes to workouts specifically, Apple rates the battery life with GPS at six hours. Given that, I would trust the Series 5 to last through a short run or even a half marathon, but I'm not sure yet how it would fare in one of my slow, five-hour marathon endeavors.

The built-in Activity app is simple and ingenious: I feel motivated to fill in my "move" (active calorie), exercise and stand rings each day. I enjoy earning award badges, even though they mean nothing. I celebrate when I meet my move goal so consistently that the watch automatically increases my daily goal. I'm grateful that the Apple Health app can pull in workouts from Garmin and every other brand featured here, and then count that toward my daily exercise and stand goals (but not my move goal, curiously).

The Apple Watch can also export workouts to MyFitnessPal so I get credit for my calorie burn there, and Strava recently updated its Apple Watch app to ingest data from the watch. The watch also has all of the advanced health features that the Series 4 did, including a built-in ECG test for cardiac arrhythmias, along with fall detection, emergency calls and menstrual tracking. New to the Series 5 is an always-on display, a built-in compass and international emergency calling.

Lastly, I appreciate that the watch automatically detects workouts after a certain period of time. I use this feature daily as I walk to and from the subway and around my neighborhood. After 10 minutes, the familiar vibrating tick, with a message asking if I want to record an outdoor walk. The answer is always yes, and the watch thankfully includes the previous 10 minutes in which I forgot to initiate a workout.

But what of running? In short, you're getting the basics and not much else. You can see your distance, calorie burn, heart rate, average pace and also rolling pace, which is your pace over the past mile at any given moment. You can also set pace alerts -- a warning that you're going faster than you meant to, for example. Given that this is an Apple Watch, you can also stream music or podcasts, if you have the cellular-enabled LTE model.

Because the watch has a GPS sensor, you can leave your phone at home while running -- which wasn't an option in earlier versions. Of course, no two brands of running watches will offer exactly the same distance readout on a run; indeed, my friends' watches and mine often disagree, even if we ran the same route side by side from start to finish. That said, my anecdotal experience is that the Apple Watch often says I ran farther than other watches would, which means my average pace is also faster than I'd expect. That last metric is the real red flag: You can convince me I ran a fifth of a mile farther than I think I did, but after a point, it's hard for me to believe I ran as fast as Apple claims. I know my limits.

On a brighter note, the Apple watch integrates with some treadmills and other exercise equipment, thanks to a two-way pairing process that essentially trades notes between the device and gym gear, formulating a more accurate estimate of your distance and effort using that shared data. The technology, called GymKit, is compatible with equipment made by Life Fitness, Matrix Fitness, TechnoGym, Cybex, SCIFIT, StairMaster, Star Trac, Schwinn and Nautilus. Support for Woodway, True Fitness and Octane Fitness is coming soon as well.

In my experience, the watch usually agrees with the treadmill on how far I ran, which is not always the case with other wearables. As such, though I sometimes suspect the Apple Watch is overstating my distance on outdoor runs, I have more confidence in its ability to accurately track treadmill workouts.

Regardless of whether you run indoors or out, all of your stats are listed on a series of pages, which you swipe through from left to right. In my early days using the watch, it was tempting to use the Digital Crown as a stopwatch button, similar to how I use every other running watch. This urge has mostly subsided as I've gotten more comfortable with the user interface. Like many of its competitors, the Series 5 has an auto-pause option, which I use often in start-and-stop workouts.

All told, this is a fairly limited list of stats, without much room for customization. There's no mode for interval workouts, either by time or distance. There's not much of an attempt to quantify your level of fitness, your progress or the strenuousness of your workouts or training load. None of this will be a dealbreaker for more casual runners. Ditto for the distance tracking; it sometimes seems slightly off to me, but it might well be good enough for someone just trying to get credit for their runs.

For more detailed tracking, your best bet is to experiment with third-party running apps for the iPhone, like Strava, RunKeeper, MapMyRun, Nike Run Club and others. It's through trial and error that I finally found an app with Watch support and timed intervals. But at the end of the day, it's easier to wear a purpose-built running watch when I'm running outdoors, sync my data to Apple Health, get my exercise and standing-time credit, and then put the Apple Watch back on the first chance I get. But if you can only afford one smartwatch for training and life, there's a strong case for choosing this one.

Garmin Forerunner 645 Music

What you get: A robust running watch with built-in music storage that doubles as a basic smartwatch. Pros: Decent battery life; useful performance-analysis features; wrist-based heart-rate tracking; built-in music storage; support for Garmin Pay; can track other sports, too. Cons: More expensive than other multisport watches, including some from Garmin; smartwatch-like notifications are crude and not very useful; locking into a GPS signal can take a while. Buy Forerunner 645 Music at Amazon - $290

For many of the marathoners I know, Garmin is the gold standard in running watches: Its devices are feature-rich, easy to use and offer long battery life. I've been living with the company's Forerunner 645 Music watch for about a year now. It's one of the highest-end models in Garmin’s running lineup, and as the name suggests, it features onboard music storage ("up to 500 songs," says Garmin), among other niceties. It's worth noting up front that if $400 feels like a lot to spend on a running watch (or if music streaming seems unnecessary) Garmin offers cheaper devices like the 245 that share much of the same DNA.

Though the 645 Music has the word "runner" in its name, I should clarify that this is actually another multisport watch, with the ability to track swimming, cycling, weight reps and more. Like many of its competitors, it lets you customize the onscreen data pages and has features like auto pause, auto lap, manual lap, heart-rate zones and alerts, and configurable intervals based on time or distance. As a fitness tracker, it tallies steps taken, calories burned, floors climbed, intensity minutes, sleep and one's overall stress level.

Things get more advanced as Garmin attempts to rate both your level of fitness and the effectiveness of your training. The watch calculates your VO2 Max -- an indicator of both endurance and cardiorespiratory fitness. In tandem, the watch also predicts marathon and half-marathon times, though in my experience (and that of every runner I know) these times are more than a little ambitious. As of this writing, the 645 Music is projecting a 3:45 marathon for me; I'd be delighted just to break my personal best of 4:52. Garmin also uses your VO2 Max to calculate a "fitness age" inside its iOS/Android app, which is more flattering than anything else. At 34, I'm told I have the fitness of an "excellent 20-year-old." Thanks!

Additionally, the 645 Music also rates your so-called "performance condition" toward the beginning of each run, a number that's based on a combination of pace and heart rate. This metric can be deflating, especially when the number is low and it comes at the beginning of a race, but you can take comfort in the fact that this number is fluid throughout the run. (You can go into the app afterward and see how your rating changed.) So what starts off as a slow, sluggish run can sometimes improve.

More useful is the feedback on training load. Scroll through the home screen and you'll see a color-coded label describing your performance condition: recovery, detraining, maintaining, productive, unproductive or (and this is a rare one) peaking. Click through and you'll see your seven-day training load with a rating appended. That number takes into account not just the number of miles you've run or the amount of time, but the relative effort put in each time. For each workout you complete, you'll see scores for aerobic and anaerobic training. Did you simply maintain your aerobic fitness, for instance, or were you also working on your lactate threshold? These post-workout summaries are a helpful way to gauge if you were hustling as hard as you could have, or if perhaps you were overdoing it.

As with all Garmin watches, I find the 645 Music easy to use, if a bit clunky. You learn quickly which button to press to start and stop a run (upper-right), which to press for laps (lower-right) and which ones are for scrolling up and navigating backward (lower-left and lower-right). My main gripes are that locking into a GPS signal can sometimes take an eternity, even in ideal conditions (out in the open, with no cloud cover or tall buildings nearby). That said, assuming you wait until you have a signal to begin a run, the tracking is usually accurate. (I base my assessment partly by running on routes with defined mileage, like a loop of my local park.) Occasionally, though, something will go awry with the GPS and my maps look like this:

I also find that everything takes a lot of clicks. After a workout, I have to click into one screen to see my heart-rate zones and another to see my aerobic and anaerobic training effect, and yet another to see my updated training load and VO2 Max. Other brands, like Coros or Polar, show me all of that one on scrollable watch screen after I complete a workout. That seems like the way to go.

All told, Garmin says the 645 Music can last up to seven days as a smartwatch, up to five hours in GPS mode with music streaming, and up to 14 hours with GPS mode and no music. That last figure is shorter than some other GPS watches, but still longer than what you can manage with the Apple Watch Series 4. For what it's worth, I've run both half marathons and marathons with the 645 Music, with plenty of juice left to spare. Personally, I use a good old-fashioned iPod shuffle or my phone to play music, but that's not to say you, too, should ignore the device's signature feature.

Or maybe that's exactly what I'm saying. It's because of its smartwatch capabilities that the 645 Music costs as much as it does, but these are also the features that I find the least useful. Even if you nixed Garmin Pay, you could get an otherwise equally capable Garmin watch in the $250 to $300 range. (That would be the Forerunner 245 or 245 Music, which also does music playback over Bluetooth.) As for the other smartwatch features, I find that text messages and other notifications on the 645 Music don't show much content and, again, it takes a lot of clicks to get there. You can at least text responses and reject phone calls on Android, but not if you're on iOS. Garmin has the ConnectIQ store for apps, widgets and watch faces, but the selection isn't compelling. At least the Garmin Connect app itself has gotten a bit cleaner over time.

In short, the 645 Music is, in absolute terms, a great running watch. But most people can safely step down in Garmin's line to something with fewer bells and whistles.

Coros Apex

What you get: A multisport watch from an up-and-coming company with slick software and tons of customization options. Pros: Easy-to-use, well-designed app; lots of watch customization options; stylish hardware with a comfortable band; long battery life. Cons: Mostly ugly watch faces; integrates with fewer third-party platforms than other watches; interval training options are limited; smartwatch notifications are too basic to be really useful. Buy Coros Apex at Amazon - $300

I'll be honest: I'd barely heard of Coros before working on this story. The company was only founded three years ago, and until now, Engadget has written about it once. But after seeing Coros' name pop up on other "best of" lists, I was curious to try it myself. I can now confirm: For a nearly no-name company with little experience making, well, anything, Coros makes a surprisingly good product.

Specifically, I've been testing the $300 Apex -- the mid-range option among the company's three multi-sport watches. The watch comes in two sizes, 42mm and 46mm, with the larger model offering longer battery life (35 hours with GPS versus 25) and improved build quality (titanium versus ceramic). I opted for the smaller edition, owing to my small wrist size, but either way, the user experience is the same.

The hardware itself is sleek as far as sports watches go, with a round face and a minimum of buttons around the outside. (More on that in a moment.) At least one other runner, who also didn't know the brand, complimented me on it. Perhaps more useful feedback: The included silicone band feels soft against the skin and straps in snugly, but not too tightly. You can also swap in standard 20mm and 22mm straps from other brands. Just as important, the device is easy to use, despite an unusual button layout. That layout includes a small knob in the upper-right; it looks a lot like the Apple Watch's "digital crown." Below that is a small button, meant for backward navigation.

That knob (delightfully called the "Digital Knob") doubles as a stopwatch button to start and pause workouts -- it also rotates to scroll through menus and data screens. Unlike the Apple Watch, which also has a knob of sorts, there's no touchscreen here, so that rotating mechanism needs to work well for general navigation. I found navigation intuitive and easy to master, and I imagine it will come in handy in cold weather when I'm wearing gloves. In a few fringe cases when I wasn't sure where to find something -- setting up interval workouts, for example -- the small number of buttons made the process of elimination easy.

The accompanying app is also well designed. Like other sports watch makers, Coros gives you the option of customizing what data shows on the watch during a workout, and in what order. But Coros elevates things to another level, with a slick interface that takes all sorts of details into account, including not just where on the data screen a metric will appear, but how much space it will take up. The process of customizing the watch was so compelling that once I set up the device for outdoor and indoor running, I was tempted to do the same for the other six sports: trail running, hiking, biking, indoor cycling, pool swimming and open-water swimming. My only complaint: The available watch faces are all some degree of ugly.

What's equally nice is that when you complete a workout, you'll see all your stats on one scrollable screen. Remember that some brands, especially Garmin, make you click around into different menus to see those stats in a more piecemeal way. Those stats include VO2 Max, a seven-day training load and a personal fitness index, similar to what Garmin and Polar offer in their respective devices.

When you finish a run, you can sync your data with popular platforms including Strava, TrainingPeaks and Apple Health. That's a good start, though I'd like to eventually see a few more app integrations, including with popular calorie counters like MyFitnessPal.

In my earliest runs, the watch was slow to lock into a GPS signal, even in ideal conditions with minimal cloud cover and no tall buildings in sight. But since then, the watch has gotten faster to find a signal, so I can begin my workouts faster. I've found consistently that the distance readout almost identically matches what my running buddies are seeing on their Garmin watches. When I check in, the two watches show exactly the same distance, or are off by perhaps a hundredth of a mile. Not bad.

Helpfully, Coros also lets you download maps onto the watch. This won't matter if you're running a cordoned-off race like the New York City Marathon, but it'll come in handy for trail runs as well as excursions in strange cities. Unfortunately, I was less impressed with interval training, which doesn't seem to have an option for letting you repeat a cycle (say, walking and running) indefinitely; the number of reps tops out at 32.

Lastly, it's worth mentioning as an afterthought that the Apex shows smartphone notifications, which is fitting because the feature itself feels bolted on. The watch will vibrate to show you incoming notifications, like texts and Google Hangouts chats. But they're not actionable in any way -- no canned responses, no nothing. I'd rather not have them at all, especially since the constant vibrations get annoying, fast.

So who is this for? Maybe not someone who requires walk-run intervals, but anyone who runs, hikes, cycles, swims (or some combination thereof) and wants a stylish, easy-to-use sports watch with long battery life. I'd say that's a lot of people, including many, surely, who have not heard of Coros.

Polar Vantage M

What you get: A multisport watch offering long battery life and impressive performance analysis for the price. Pros: Slightly less expensive than the competition; tracks many kinds of sports; lots of data, especially for a device in this price range; battery life is some of the highest in its class; quick to find a GPS signal; integrates with many popular health and fitness platforms. Cons: The watch itself can be difficult to navigate, while the accompanying app also feels crude; included band feels cheaper than on rival devices. Buy Vantage M at Amazon - $280

Polar is no underdog in the sports watch space: An elite runner I interviewed for this very gear guide swears by the company's high-end Vantage V watch. So it made sense to include the Finnish company in my testing. But for the purposes of this story, It felt it better to focus on the Vantage M, the company's mid-range model, which tracks not just indoor and outdoor running, but nine other sports as well. Truth be told, it offers many of the same features as the V, except that it has no touchscreen; the battery life is shorter (30 hours versus 40 on the V); it's water resistant up to 30 meters instead of 50; it lacks audio alerts; and it's lighter-weight (45 grams, versus 66g).

One nice difference between the two watches is that whereas the V only fits proprietary Polar wristbands, the M will take any standard 22mm strap. That's a good thing, because the band that comes in the box feels a little cheap and is also a little kludgy to fasten.

Speaking of kludgy, neither the watch itself nor the accompanying app is particularly easy to use. The watch features three buttons on the right side and two on the left. As you might expect, the middle-right button functions as a stopwatch for starting workouts. But if you try and use that same button to pause a workout (understandable), you're actually recording a lap; you need to press the lower-left button to pause, and long-press it to finish and save a workout.

Things get even more confusing when you attempt to use the lower-left button to scroll through menus; it's actually a back button. Instead, the top-right and lower-right keys are meant for making selections. It feels odd to me to have these on the same side of the watch, and not on either side. Even now, after weeks of testing, I routinely back out of menus when I'm actually trying to move deeper into them.

As for the app, it's clearly labeled, to its credit, but less slick than what Apple, Garmin and Coros have to offer. I also learned the hard way that I need the app to enable interval training on the watch, which feels unnecessary; other watches let me create interval workouts on the device itself, without any intervention from my phone. On the brighter side, I appreciate that when I have an interval workout set up, the watch vibrates several times as a warning that I'm about to finish a segment and transition into another. These multiple vibrations also helps me differentiate from a lap, which also vibrates just once. Another tick in the software positive column: Polar integrates with a healthy assortment of third-party platforms, including Apple Health, Strava, TrainingPeaks, MyFitnessPal and Nike+.

In practice, the GPS sensor is quick to lock into a signal, which is a plus. While you work out, the watch uses a built-in optical sensor to monitor your heart rate. Like other advanced watches, Polar then uses that data to calculate your VO2 Max and training load, including cardio, muscle and "perceived" loads. (The muscle load analysis requires oan extra sensor; on the higher-end Vantage V, it's built in.) You can also program both heart rate zones and speed zones, building on the more basic speed alert feature you'll find in, say, the Apple Watch.

At the more basic end, as you might expect, the Vantage M also does basic activity and sleep tracking. The company also says an inactivity alert is coming in a future firmware update -- which, if it's what I imagine it to be, it sounds a lot like the Apple Watch's nudges and Garmin's terse "move!" alert. Surprisingly, the Vantage M doesn't do much in the way of smartphone notifications, but I think that's OK. I'd rather Polar not add more cruft to its confusing interface, especially if it's going to just half-ass the smartwatch experience like Garmin and Coros did.

If it sounds like I'm being harsh on the Vantage M, in a way I am. I hope the company rethinks the user interface, particularly on the watch itself. But there's still plenty to like here: You get long battery life, quick, accurate GPS and some advanced performance tracking features, all for a slightly lower price than competing watches. That alone makes it worth a look. If you can learn to master the quirky user experience, then you'll find the hardware is exactly what it needs to be.