BATTERY LIFE SUCKS :
Regular use will provide you with up to 18 hours of Battery life, but demanding apps — which, let’s face it, we all use — will diminish the battery’s lifespan by about three or four hours ( but perhaps less depending on your personal settings) . For a health and fitness-tracking watch, the sole purpose of which is to track your physical activity and vitals around the clock, that’s not very good.
Too little screen:
Simply put, there’s not enough display real estate. Developers with successful apps will be forced to completely revamp their creations to fit the new medium, and they may not want to do that if they don’t see an obvious monetary incentive to do so. It’s for this reason that most mobile gaming companies won’t go anywhere near the device.
And The list goes on:
Apps function poorly.
It actually requires two hands ( what? ).
Navigation sucks.
Communication functionality sucks.
Music-playing sucks.