Horrible tracking and User interface
The default tracking is horrible, it skips many hours of sleep or sometimes it does not even count it. If you try to adjust it in the app it gives you other estimations that are just as bad. Also it messes up the sleep from apple itself. The base tracking is much better, if you want more information about sleep data use the sleep app. This is no worth the price and time it takes to configure it The user interface is also a mess, too much information The only positive is that it is very customisable regarding to the calibration but again, not worth the hassle since the default is so bad
