Im giving this app a 2 stars review for one major issue... It refuses to sync with my Polar M400. After the initial sync when I paired the app with the watch, no matter how many times I try to sync, it wont make connection with the watch (and yes, the iPhone shows connection to the watch). Other than that, the app displays a lot of information (same info that can be found online by the way, but faster to use with the app), plus it allows interaction with the data, which can be useful for some, but for me it doesnt make a difference. Again, my main issue is the fact it doesnt sync with the watch.