Simply put, the battery sucks. Its a deal breaker. Im really sorry to say that, too. In fact it hurts me because I wanted this phone so bad, but the battery life is horrible. The phone will lose a third of its battery sitting overnight with the GPS, WiFi, and 4G turned off. Even with Advanced Task Killer set to aggressive and auto killing apps every hour, the most I can get out of the phone is about ten hours.
Take yesterday: I pulled it off the charger at 9 am, checked my mail and ESPN a couple of times during church, used the GPS navigation for 13 miles, and then checked my mail a few times throughout the afternoon while I was at a family event. The phone died promptly at 6 pm. Its that bad.
Ive tried a few different things like using a static background rather than a live background, turning off widget animation, disabling WiFi/4G/GPS, and setting Advanced Task Killer to aggressive. Nothing makes a significant difference. The phone just sucks the battery dry.
So heres the problem. Power users are the ones that can fully take advantage of the large screen, but the more they use their phone, the faster it dies. The only way I can see to counter this is to plug in the phone whenever possible. When you sit down at your desk, plug it in. Drive to the store, plug it in. Go to bed, plug it in. You might want to invest in one of those instant charge battery packs, too.