3G only here. I was dissapointed in the battery some. I've made some small changes here and there to help it out and now I'm fairly satisfied batterywise overall. I had a couple apps that KILLED the battery. Super KO Boxing 2 for instance. I downloaded so my kids can play it on the weekends, but I ran it for just a couple minutes to download the necessary extra file framework and started the app to make sure it ran ok. Got out of it and went on about my business. Looked later in the day and it had taken 10% of the 70% of the battery used (down to 30%).
I can foresee an app in the future switching 4g off/on depending on the state of the phone though.
Today 4hr 38minutes since off the charger and at 80% with moderate, but not HARD usage. Some web, downloaded an app, played with some settings, a couple phone calls, some texts, etc
I don't know weather its my tweaks I've made, but the battery continually gets better each day.