I've been really impressed. I have the smaller size and was worried when everyone started talking about it probably not getting as long a battery life as the larger size (smaller size, smaller battery) but I've easily got about 30% left in my longest day and I'm using it a lot... and showing it off to friends and strangers a lot. I use the fitness tracker in the morning, check emails and reminders all day, use it to control my iPhone podcasts, pinged my iPhone twice already (can I say that little feature is awesome!) and used the map. The map seemed to drain it the most but it was still acceptable and I won't use it for long trips anyway.