The Series 4 now has several new health-focused features, which are very intriguing, including the ability to detect when you fall and even alert emergency contacts if need be, as well as an electrical heart rate sensor that works with an app to alert you to heart health issues. The electrocardiogram (ECG) app has been certified by the Food & Drug Administration, but it's not out yet.
If you want the app, notification, and style advantages of an Apple Watch but need better fitness tracking, you can upgrade to the Apple Watch Series 3 and get built-in GPS, as well as waterproofing that allows swim tracking. But the Series 3 costs more than a fitness tracker or even many running watches, and it still has compromises compared with a dedicated fitness tracker, such as a lack of dedicated physical buttons. We think serious athletes are better served by a fitness-specific device.
Battery life and charging options: Charging your smartwatch is a hassle and the biggest downside to trading in your manually-wound or button battery-powered watch. A Fitbit Versa might last 3 - 4 days between charges, but a smartwatch like the Samsung Gear Sport or Apple Watch will need recharging every couple of days and sometimes every night if you are tapping on the screen regularly and using its apps.
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.