What is it?
At first glance it looks a lot like a Swatch: a cheap(ish) plastic analog watch. And it certainly does everything a Swatch does very well: it tells the time, it's waterproof, it's comfortable.
The Withings Activité is, of course, more than just a watch: it's also the first ever activity tracker which doesn't make you look like a bit of a dork. I've been wearing the original for just over a month now; the Pop is basically the same thing, at just one third of the price. My verdict? I agree with the crowds: this is the best activity tracker yet. What's more, it's likely to stand the test of time much better than the Apple Watch.
The genius behind the Activité is that it doesn't have any kind of electronic screen. In order to tell the time, or see how many steps you've taken, you don't need to tap it, or twist your wrist a certain way, or make something glow, or use your other hand at all. All you need to do is look at your wrist. It's a use case which has stood the test of time. Wristwatches are vastly more popular than, say, pocket watches, and yet this is the first activity tracker which works like a wristwatch. If you're on your bike and want to know what the time is, the Activité will tell you. No other activity tracker (quite possibly including the Apple Watch) can do that. Sometimes, old tech is the best tech. As Activité CEO Cedric Hutchins says, it's "instant and intuitive". In fact, it's even more intuitive than an old-fashioned wristwatch, since it automatically adjusts the time when you change time zones or the clocks go forwards or back. You never need to fiddle with anything to set the time.
The Activité is also the first activity tracker without built-in battery anxiety: it works for eight months at a stretch. Because of that, and the fact that the Activité is waterproof, you can basically just wear it 24 hours a day. It will track your steps, and your sleep, without you having to do anything at all. (The more expensive version comes with two straps, one of which isn't waterproof. That's one reason to wear the other strap all the time, even in the shower. Another reason is that the waterproof strap is incredibly comfortable.)
What's more, because most of the technology is in the Withings app (which communicates with the watch via bluetooth), the watch can get better over time. Right now, for instance, it doesn't sync in the background, and it can't tell when you're running or swimming, and it is locked to a default steps goal of 10,000 steps per day. But with the next app update, all of that will change. The dial which measures steps, for instance, goes up to 100%, not to 10,000 steps, so it's easy to change the goal without changing the watch.
On top of that, the watch vibrates, a feature which might well get used a lot more in future updates. Right now there's just a slightly fiddly alarm function, but I can easily see a future where a subtly vibrating watch will alert you that your phone is ringing. (Fitbit has already implemented that feature, which is very handy, especially when your phone is in a bag in a noisy bar.) The watch can even tell when you double-tap it, if it's been stationary for a couple of seconds. I'm not sure how that's going to be useful, but they might think of something.
The Activité is still a 1.0 device — it's just one of the best 1.0 devices I've seen. A couple of improvements I'd like in version 2.0 of the watch: firstly, some kind of light, or way to tell the time in the dark. The sleep tracking feature encourages you to wear the watch in bed, so it's only natural to want to use the watch to tell the time when you wake up. It would also be great if the step tracker was a full 360-degree circle, rather than a 270-degree wedge. It would make milestones like "you're halfway to your goal" even more intuitive — and, more importantly, it would allow the tracker to keep on rotating even after you reached your goal, so you could tell when you were on track for a 15,000-step day. (Yes, 15,000 steps would look the same as 5,000 steps, but you're going to know which is which: it's entirely analogous to 7am looking the same as 7pm.)
Finally, a tip, for anybody who buys this watch: it's so easy to use that you forget it actually has a button, on the back. If it ever goes wrong, you poke the button with a pointy thing, and it resets. (You might need to restart your phone's app, too.) The reset even remembers the time and the number of steps you've taken. That's pretty much the entire operating manual, right there. There's no learning curve, there's no feeling that you're an early adopter of often-befuddling new technology. There's just a handsome watch, which does what watches do, while at the same time quietly encouraging you to get out and walk more, and to get a better night's sleep. At $450, I liked it a lot. At $150, it's an unconditional buy.