The operating system you choose depends solely on the type of smartphone you have because the smart watch is paired with your smartphone. If you own an Android smartphone, your smart watch should have Android Wear or Tizen. If you own an iPhone, choose an Apple Watch. For example, the Samsung Gear S3 runs Tizen and is compatible with both the Android and iPhone.
Huawei’s Watch 2 looks like a logical follow-up to the original Huawei Watch, a former pick in this guide. It adds built-in GPS capability, plus NFC for mobile payments, and it ships with Android Wear 2.0. The problem is that the Huawei Watch 2’s bezel does not rotate, and it has no rotating crown to take advantage of Android Wear 2.0’s scrolling interfaces. That wouldn’t be so bad if the thick, notched bezel weren’t significantly raised around the screen, making it more difficult than it should be to swipe between screens, scroll through apps, or perform pinpoint taps near the edge of the screen. Beyond that, the watch is thick (12.6 millimeters, or 2.6 mm more than the ZenWatch 3, though that’s still slightly thinner than the original Huawei Watch), and it seems slower to respond to input and to launch apps than other modern Wear OS watches. It doesn’t seem worth its price for most people.
For deeper integration with your Android phone, you can give Google's Wear OS platform a try with Fossil's $275 Q Control touchscreen smartwatch. It lacks GPS and support for NFC payments, which is why the Gear Sport is a better fitness-focused smartwatch for Android users, but Fossil's Google Assistant integration and stylish design make it a solid contender. However, smartwatches with Qualcomm's new Snapdragon Wear 3100 processor start shipping in October, so you may want to hold off until we put them to the test.