I'm a bit of a slave to my FitBit, but am considering switching to an Apple Watch b/c the Apple Watch has some other features that are important to me (fall detection, cellular, and the ECG). I'm having a hard time deciding what to do. Has anyone here used both and have a preference? If you use an Apple Watch to track exercise, do you find it to be reliable? Are you glad you bought it? Given a chance to do it over, would you buy it again? One of my main concerns with switching over is that I have no idea how to track calories with Apple's apps and such. I'm an Android user, so everything Apple is brand new to me (I'd have to get an iPhone, too). Advice? Cautions/warnings?