Bottom line: Some fitness trackers work equally well with an iPhone or Android device, but some smartwatches are built to pair with Android phones so you won’t enjoy full functionality and pairing on an iPhone. The Apple Watch only pairs with the iPhone so is off limits to Android users. Your existing phone choice will play an important part in choosing a smartwatch. You can check your smartphone’s compatibility with a range of Google Wear-powered smartwatches at g.co/WearCheck
If you want a smart watch that uses cellular data without using up the battery, consider upgrading to the Samsung Gear S3. A close cousin to the Gear Sport, the S3 has all the perks of an LTE smart device (downloading apps, texting, checking email) and, unlike the Apple Series 3, it won’t quit after three hours. In fact, you could feasibly get 72 hours out of this LTE version of the Samsung Gear Sport.
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.