The Amazfit Bip is thin and light, looks like an Apple Watch, has a lot of sensors inside—GPS, heart rate, accelerometers, barometer, and compass—and can run for about 30 days (which we confirmed) between charges, all for around $100. Those facts are compelling, but actually using the watch is frustrating, and it doesn’t do any one thing well. The GPS and heart-rate monitors can be slow to start, sometimes drop out, occasionally have wild inaccuracies, and produce results notably different from those of running watches and dedicated fitness bands. The screen is also dim and noticeably low-resolution, and the phone software for managing the watch is dense and unintuitive on Android. (We didn’t test iOS, but the reviews imply that it’s not much different.) The watch materials are plastic and rubber, and look and feel like it. Those are all trade-offs you could reasonably make if you just wanted a Pebble-like smartwatch that tracked steps and showed notifications, but even there, the Bip does not succeed: It often dropped connectivity with my phone (a Pixel 2), and it cannot show emoji—getting a dozen blank squares when someone sends you a thumbs-up sign is not helpful. If all you care about is battery life, the Bip has that, but it lacks useful functions while it’s charged up.
Smartwatches, like smart phones, can also run apps, via your smart phone or right on the watch. These include health and fitness apps (thus the comparison with activity trackers), apps that control functions such as music and the camera on your phone, navigation apps, and more. Because most smartwatches have open software platforms (at least so far), developers are coming up with new and innovative apps that can increase the functionality of the devices.

The Apple Watch Series 4 is now on sale, and it's the best smartwatch you can buy right now. The redesigned device, which starts at $399 for the GPS model and $499 for the cellular version, is the best smartwatch you can buy. It has a larger display and slightly bigger case size while retaining the same rounded square design the watch is known for. Even more importantly, Apple received FDA clearance for a new electrocardiogram feature that can take a 30-second EKG and diagnose atrial fibrillation.