The greatest Apple product comeback story of the past few years has, without a doubt, been the Apple Watch. Launched with great fanfare four years ago, the initial version tried to do way too much with way too little, and it had confusing software to boot. Worst of all, it was unclear what the original Apple Watch was even for. No single thing stood out.

Then Apple did what Apple often does: iterated, refined, and fixed. But as much as there were software and hardware improvements to the Series 2 and Series 3, the most important refinements were to the Apple Watch’s purpose. It gained clarity. It was for fitness and notifications. Eventually, when it was ready, Apple added better connectivity.

Now, with the Series 4, Apple is iterating again. And, importantly, it’s learned how to iterate the product’s hardware and its purpose at the same time. The Series 4 has finally achieved something like the original goal of the Apple Watch. It’s not quite a do-anything computer on your wrist, but it can be different things to different people now.

With apologies to the new iPhones, the Apple Watch Series 4 was the most impressive thing Apple announced last week. After using it for the past week or so, I think it lives up to the hype.

For the first time since the original Apple Watch, the hardware has been fully redesigned, with a new body and new sizes. But it’s not a major overhaul. These still look like the Apple Watches you’re used to: they have the same rounded-corner lozenge shape, the same glass that curves around to match the body, and the same digital crown and single-button layout.

Before we get too far, we should talk pricing. This Watch is not especially cheap. The smallest, least expensive model comes with GPS and Wi-Fi and costs $399. But if you start piling on the upgrades, you can quickly jack up the price to something that feels exorbitant, especially if you’re upgrading from a Series 2 or Series 3. It’s $29 more for the larger size, $100 for LTE compatibility (plus $10 per month or so from your carrier), and the stainless steel models are $200 more (and only come with LTE). Add in Apple Care, and you can end up spending a lot — though it’s nothing like the wild “Edition” prices of yore. (Don’t even get me started on the Hermès model.)

The larger sizes don’t feel that much bigger than the older models

The two new sizes are 40mm and 44mm, but they really don’t feel that much bigger on your wrist than the old sizes. I was using the 42mm Series 3 and the 44mm size is only subtly bigger, but it’s also subtly thinner. To me, it feels about the same, but I think the trade-off of size for thinness is worth it. I suspect the same will be true for people who prefer the smaller size, but my recommendation is to go to a store and try one on before buying.

I’m really happy — and impressed — that Apple managed to make existing Watch bands fully compatible with the new sizes. Even my old third-party bands fit seamlessly into the new Watch body.

Things look different when the screen turns on. The screen on the Series 4 is just incredibly good. Apple says it’s 30 percent bigger, which is one of those specs that’s easy to just sort of pass over when you read it. But 30 percent is a lot, and you absolutely notice it right away.

It’s still OLED so the blacks are truly black and blend into the watchface glass. But if you pick a full-screen watchface, you’ll see that the screen also goes closer to the edges of the Watch than before, including the rounded corners.

The overall effect makes the square display on my Series 3 look dumpy and cramped by comparison — even though, until last week, it was arguably the best smartwatch screen on the market. As John Gruber writes, “The Series 4 displays take up so much more of the face of the watches that the new 40mm watch’s display is larger than the display on the old 42mm models — the new small watch has a larger display than the old large watch.”

Beyond the size and the screen, there are a few other subtle exterior differences to note about the hardware. The rear of the Watch is now ceramic instead of metal to allow for a better wireless signal. If you spring for the LTE model, the garish red dot on the digital crown has been replaced with a much more subtle red ring.

The microphone has been moved between the two buttons so that it’s further away from the speaker to help reduce echo in calls. The speaker has been boosted to provide more volume. It really is way louder, and I haven’t heard any distortion during phone calls.

Last year’s Apple Watch had some issues with LTE at launch, though Apple fixed it up fairly quickly. This year, I haven’t had any major problems with LTE. In fact, several people I called with the Watch simply didn’t believe I wasn’t on a phone. It sounds good, and the louder speaker means you can hear it without holding the thing next to your ear.

But it does take the Watch a minute (sometimes two) to switch on LTE and get connected. That’s not radically worse than what happens when you pull your phone out of airplane mode, but on the Watch, it’s always a little less clear what’s happening and why when data is not coming in.

On the inside, there’s a faster S4 processor, a W3 chip (which is just Apple’s W2 chip with Bluetooth 5.0 support), and an accelerometer and gyroscope that are able to take samples of your movements more often (which is how Apple was able to add the new fall detection feature). Apple’s also tied haptics to the digital crown, so when you spin it, you feel little ticks that precisely correlate to what’s happening on the screen. It’s completely unnecessary but pretty neat.

Battery life has been stupendous

Last but certainly not least: the battery size is about the same. Battery life on the Series 4 is as good or better than on the Series 3 Watch. Apple claims 18 hours of regular use or six hours of outdoor workouts. I haven’t done a six-hour outdoor workout (and I don’t plan to), but my testing shows the battery life far exceeds Apple’s own claims.

I took the Watch off the charger on Saturday morning and wandered around Oakland for four hours while disconnected from my phone. I used LTE for maps, a couple calls, and GPS for tracking my outdoor walk “workout.” I was still at 50 percent at the end of that day, and I didn’t get below 20 percent by the end of my lazy Sunday (which also involved an hour or so of GPS tracking and some LTE data).

The battery life is so good that I wish Apple gave me an option for an always-on ambient screen, maybe by turning off some radios. Alas, you still have to turn your wrist to see the time.

watchOS 5 is kind of a grab bag of new features, which sounds dismissive, but I don’t mean it to be. It’s a good sign that watchOS is ready to be laden with features instead of rethought from the ground up, as it was in years past. There’s support for podcasts, Walkie Talkie mode, slightly improved (and grouped!) notifications, and a bunch of fitness and health options.

But the thing people will probably pay the most attention to are the new watchfaces that are available on the Series 4 Watches. They’re designed to show off the new rounded-corner screen. Some are just sort of flashy animations, while others are chock-full of new complications in phantasmagoric colors.

Of the new watchfaces, I am most fond of the animated ones. Apple says that the fire, water, and vapor animations were all created with practical effects. As in: literal fire, vapor, and water were filmed with high-speed cameras as they flowed on custom-welded rigs. They look great; the animations naturally flow right up to the rounded corners.

The watchface that you’ll probably see the most in ads is called “infograph.” It takes the bigger screen of the Series 4 and fills it up with as many as eight complications. There’s a “modular” version as well that shows the digital time and six complications. Like many parts of watchOS 5, they use new, more rounded fonts, too.

The infograph watchface is polarizing. I don’t like it at all, though I wouldn’t go so far as to call it a “design crime.” There are just too many colors doing too many different kinds of work splashed all over the screen in a garish and show-offy way. Too many of Apple’s watchface options are like that. Call me boring, but I prefer a Watch look that’s a little more staid. It makes me a little sad that Apple still doesn’t allow third-party watchfaces.

Even if you like the new watchfaces, you probably won’t like what happens when you try to select a new complication. There are now “old”- and “new”-style complications, which are completely different and incompatible. The newer watchfaces need the new complications, so third-party developers will have to update their apps (and so will Apple). You can’t add the Home app to the new watchfaces, only the old ones. The most annoying part is that there’s no way to know what complications are available on any given watchface without scrolling through and looking for the one you want.

On the fitness front, the best new feature is automatic workout detection, which can tell if you’ve started or stopped a workout and ask you if that’s the case and if you want to log it. There are now options for yoga, hiking, setting a target pace, and tracking your pace. You can also see your cadence as you run and challenge somebody to a week-long exercise competition. (I didn’t extensively test these features; I’m still at the “fill your damn rings” stage of my exercise goals.)

Maybe the most interesting change, though, is how Apple is more clearly separating out health features from the fitness stuff. There are a few new features in watchOS 5 and the Series 4 that are designed to help you detect health problems, not just encourage you to close those activity rings or run a marathon.

That’s interesting because it more explicitly positions the Apple Watch as a device that can help detect health problems, making it something that people who can’t exercise that much might be more interested in. Apple, as always, is very careful to not cross the line into making actual health claims about its new features. It’s careful to say that the Watch can detect things like irregular heartbeats, not that it will.

There’s a big difference between “tracking your fitness” and “monitoring your health”

watchOS 5 is able to detect low heart rate now, in addition to high heart rate. Later this year, Apple will add detection for irregular rhythms and provide notifications for them. The big new feature on the Series 4 is that it can take an electrocardiogram (EKG) using electrodes built into the back of the Watch and the digital crown. It can then send a PDF of your results to your doctor. I wasn’t able to test that as it is coming later this year. Both irregular heartbeat detection and the EKG features have been granted “de novo” classification by the FDA, and that distinction is important, as Angela Chen explains:

It’s important to understand that the FDA has “cleared” both apps, but that’s not the same as “approving” them. There are usually three ways to get the FDA involved in a new project, according to Jon Speer, co-founder of Greenlight Guru, a company that makes quality management software for medical device companies. The most advanced is FDA approval, which is done only for Class III products, or technologies that might have higher risk but also a higher benefit. (Think: implantable pacemakers.) Approval is the gold standard, and companies need to do a lot of testing to receive this designation. The Apple Watch is in Class II. For Class II and Class I, the FDA doesn’t give “approval,” it just gives clearance.

Another new feature exclusive to the Series 4 is hard fall detection, thanks to a new 800Hz accelerometer and gyroscope that can that can measure up to 32 G-forces. The Watch should be able to tell if you’ve had a spill and ask if you’d like to call emergency services. If you don’t move for a full minute after falling, it can do that automatically and also send a message to your emergency contact. Apple is turning it on automatically for users who tell the Watch they’re over age 65, and it’s making it an option for younger users as well.

I’ve tried to trigger it without hurting myself and I haven’t been able to, which I suppose is a point in the Watch’s favor. (My tests were far from scientific; I was just hurling myself at the couch.) Apple says that to build its fall detection algorithms, it used data from a study involving 2,500 participants over several years, and it also worked with assisted living facilities and movement disorder clinics.

So throwing yourself into bed after a long day shouldn’t trigger it, but a fall from a ladder or tripping over a curb and flailing your arms as you hit the ground might. Again, Apple’s health claims are not that the Watch will detect these falls, but simply that it could.

A lot of people were really excited about Walkie Talkie mode, but after testing it, I don’t think it’s especially compelling. Unlike those classic Nextel Push-to-Talk phones, Walkie Talkie mode on the Apple Watch is essentially just a FaceTime Audio call with a button you press to talk and little beeps and visual indicators to tell you if it’s your turn.

When you send the first message, you have to wait for a connection to be made, and then it’s just tapping the screen and talking. The connection stays active until a few minutes after the last person finishes speaking. It’s neat, but it doesn’t feel as instant as a true PTT system. I also had connectivity problems with it, but that may have just been OS launch-day overloading.

That said, it’s silly fun to push the big yellow button with your nose when it’s your turn to talk. I strongly recommended it. (If it becomes a thing, I want to make sure I get full credit for coining the term “nose calls.”)

Siri on watchOS 5 is still Siri. There’s a new feature that lets you simply lift your wrist and start taking instead of pushing a button or saying “Hey Siri,” and it works really well. The Siri shortcuts you set up on your iPhone should also work from your Watch, too. Siri still feels super unreliable, though.

Siri gets especially fussy when you have a spotty connection. Too often, when I wanted to ask a question, I’d be met with a “hang on…” message, followed by a “I’ll tap you when I’m ready” message, followed by an interminable wait during which I’d forget whatever it was I needed Siri for.

One last little watchOS 5 thing I must mention: you can open links to webpages now, too, which is kind of fun. Articles you click on get put into readability mode, so you don’t have to worry too much about ads or bad layouts on your Watch. Hooray for the web!

This year’s Apple Watch is incredibly good. If you use it just for notifications and step counting, it’s probably overkill, but it’s able to handle more advanced features better than any other smartwatch I’ve tested. Mapping, music, workouts, calls, texting, podcasts… most of the stuff I could imagine wanting from a smartwatch works better than ever before. The only real bummer is that I still don’t feel like I can trust Siri to do everything I’d like reliably, and that’s more of an intermittent hassle than a real killer.

If you’re looking at this Watch with an eye toward the health features, I have to admit that they’re difficult to test: the new features could be very compelling to a lot of people. Passive monitoring for heart problems and falls could literally be lifesavers, but they aren’t all available yet, and we’d need to see third-party lab testing to really make a call there.

The Apple Watch has earned its place as the best-selling watch

For people who are looking to upgrade an existing Apple Watch, that’s a harder question to answer than usual. Spending four to six hundred bucks for a bigger screen is a luxury I wouldn’t casually recommend to anybody, even though the screen is wonderful. Many of watchOS 5’s best features will work fine on more recent Apple Watches, too. Yes, there are exclusive watchfaces on the Series 4, but that’s also a silly thing to drop so much money for.

What I can tell you is this: the Apple Watch has earned its place as the best-selling watch. It’s at least an order of magnitude better than other smartwatches and fitness trackers. Nearly everything it is designed to do, it does very well. It’s not yet a general purpose computer for your wrist, but, thankfully, Apple isn’t aiming for that anymore. The Watch is for doing little bite-sized versions of phone things like texting and listening to music, it’s for fitness, and it’s for health monitoring.

Now that Apple has figured out what the Apple Watch is for, the Series 4 just makes it better.