I sit at a desk too much. I drink too much coffee. I don’t sleep very well. I have an odd feeling those three things might be connected. This thing on my wrist agrees with that assessment.

After a few months of wearing and interacting with a fitness tracker, I have a shockingly clear picture of my lifestyle. Some of the news is good (living far from the subway is actually a good thing), some is bad (seriously: too much coffee), but it’s all eye-opening. And with the right device, it can be legitimately life-changing.

Fitness trackers will someday be obviated by smartwatches, smart clothes, and smart-everything-elses, but for now they’re the best and most accessible way to track your activity and even take steps to improve it. They’re inexpensive, they go everywhere, and they all count your steps. None are perfectly accurate, some are remarkably not so. But they’re made to be simple, quick ways to get moving a little more.

The good ones can also track your sleeping habits, or help you track what you eat. But the best ones actually do something with all that data, beyond just putting it into pretty charts. They’ll crunch the numbers and tell you maybe you should stop drinking coffee so late at night, you idiot. Or that you tend to be more active throughout the day when you eat right after you wake up.

A few fitness trackers try to really change the way you live. Only one succeeds.

The Winner

Yes, it counts your steps. It even plots them on a lovely graph, and gets excited for you when you hit your goal a few times in a row. But the best thing about the Jawbone Up24 is what happens when you miss your goal. If you miss a few days in a row, you’ll get a gentle reminder that hey, you might want to get up and get around a little bit extra today. If you’re nearing the end of the day and haven’t quite hit your goal yet, your Up24 will send a push notification encouraging you to muster up the energy to hit 100 percent.

This is what makes the Jawbone Up24 most special. Not only does it do everything it ought to, like tracking steps and sleep, it actually turns that data into something useful. My favorite feature might be the vibrating alarm clock, which wakes you up at the perfect point in your sleep cycle. There’s also the “Today I Will” feature, which asks you to buy in on one good-health change that day: get in bed by 10:30, or bump up your step count by 25 percent. No other device does such a good job combining sleep, activity, and diet (the Up app makes food-tracking really easy) into small bits of actionable information designed to get you in better shape.

Jawbone’s open platform also means that other apps can take advantage of its data. Apps like My Fitness Pal and Runkeeper can tap into its data, and you can even set it up with Nest or SmartThings to have your house respond to when you’re going to sleep or waking up. If you’re tracking your diet, connect it to an app like HealthyOut and your Up will record your food as soon as you order it. Jawbone smartly knows that your daily step count is only part of being healthy, and that a lot of things contribute to how you feel at any given moment. The Up is made to connect to them all.

The bracelet itself sits somewhere between gadget and jewelry. The ribbed, rigid band comes in a number of colors — I wear an orange one — and though I wish it were thinner and that it had some sort of display, it’s perfectly comfortable to wear all day and night. I hate the awkward charging pin and cap that I’m definitely going to lose, but the battery lasts a week or more between charges anyway.

The Up24 isn’t the only way to track your activity, and it’s not even necessarily the most powerful. Other devices might track your heart rate or your blood-oxygen levels. But nothing else so powerfully packages that data in service of making you a healthier, fitter, more active person. And that, after all, is what a fitness tracker is all about. The Up24 is the best of the bunch.

The Runner-Up

Our review of Garmin Vivofit Verge Score 7.9 out of 10 Buy for $129.99 from Garmin

Let’s say all you’re actually looking for is a thing that will track your steps. If that’s really the extent of your feature list, buying an Up24 is like setting up a construction site, blocking traffic for weeks, and inventing an entirely new category of tools just to hammer a nail. If you just need a step tracker, the Garmin Vivofit is the one you want.

The Vivofit isn’t especially attractive, or even really designed. It’s just a small core that goes into a rubbery bracelet in a variety of colors, with a simple display that scrolls between the time, your step count, calories burned, and a few other metrics. An ominous red meter slowly fills at the top; when it fills up, you’re supposed to get up and walk around. Garmin’s companion Garmin Connect app is just a venue for charting your progress over time, and for rudimentary conversions from steps to calories. It has some handy goal-setting mechanisms, and does some extremely basic sleep-tracking, but those aren’t terribly powerful. The Vivofit doesn’t do much, but that’s by design.

The upside is that the Vivofit is dead simple to use, and to figure out. Garmin can also power the whole thing on a watch battery, which means you’ll only need to swap batteries about every Thanksgiving or so. It’s a perfect entry-level device, maybe the one to help you build the habit; it might also work for people who are already active and just want a goal to hit. It won’t replace the power of the Up, but it’ll count your steps just fine.

The Others

Our review of Misfit Shine Verge Score 7.2 out of 10 The Shine’s best feature is that it looks quite a bit like jewelry; there’s no way to tell you’re wearing anything electronic. And Misfit has big plans for opening up its data, but for right now it’s Misfit-only, overly simple-only, and the Android version has some catching up to do. The Shine is one to watch, not yet one to buy. Buy for $94.99 from Best Buy Buy for $99.99 from Misfit

Our review of Fitbit Flex Verge Score 8 out of 10 Fitbit’s Flex is a lot like the Up24, only a little more comfortable, a little less attractive, and a lot less powerful. It does its job well, but there’s not nearly as much room to grow as with the Up24. The Force is the most powerful Fitbit device, but unfortunately it’s not on sale anymore – if you want a Fitbit you should wait for the next one. Buy for $99.99 from Best Buy Buy for $99.95 from Fitbit

Our review of Withings Pulse O2 Verge Score 7.1 out of 10 Withings has a nice ecosystem of products and apps, and the Pulse O2 is a solid step-tracker, and I like that it tracks your blood-oxygen levels — though it’s not great-looking and can be finicky to use. But when the Up24 can plug into Withings as well, you might as well buy the better bracelet. Buy for $119.99 from Best Buy Buy for $119.99 from Withings

Our review of Jawbone Up (2nd generation) Verge Score 8 out of 10 The regular Jawbone Up is exactly the same as the Up24, except this older model doesn’t offer wireless syncing. And wireless syncing kind of changes everything. Without frequent data, the Up app can’t make smart recommendations to you throughout the day, or connect to other apps and services. Pay for the syncing. Buy for $79.99 from Jawbone Buy for $70.99 from Best Buy

Our review of Fitbit Zip Verge Score 7.5 out of 10 If you’re looking for a tracker you don’t have to wear on your wrist, Fitbit’s hard to beat: it's been doing this thing as long as anyone. The Zip does its job tracking your activity, and it’s cheap as well. But mark my words: You will lose this thing. You will. It’s just inevitable. Buy for $49.95 from Fitbit Buy for $48.99 from Best Buy

Our review of Basis Band (Carbon Steel Edition) Verge Score 6.9 out of 10 The Basis Band is the tracker for the hardcore. It measures steps and sleep, but also skin temperature, perspiration, and your heart rate. But it tries to do too many things, and does it all without really helping you do anything with all the data it collects. Cool life-logger; mediocre fitness tracker. Buy for $149.99 from Basis Buy for $149.99 from Best Buy

Our review of Samsung Gear Fit Verge Score 5.5 out of 10 The Gear Fit is more smartwatch than fitness tracker – it gets notifications from your phone, and can even accomplish some basic tasks on its own. But it’s not a very good smartwatch, and it’s a needlessly complicated, awkward, hilariously inaccurate fitness tracker as well. The curved display is awesome, but that’s about it. Buy for $149.99 from Samsung

Our review of Huawei Talkband B1 Verge Score 5.5 out of 10 From the land of crazy ideas comes the B1, a fitness tracker that pops out of its case to become a Bluetooth headset. That’s more useful than it sounds, but it makes the TalkBand package big and clunky and hurts its battery life. Just get a Bluetooth headset.