Initial Battery Test
So far it is really good.
I read for 3 hours with screen brightness level set to apprx. 1/3 and only used 20% of the battery charge. That is the battery discharged from 100% down to 80% after 3 hours.
BTW, I was lucky to get 3 hours of reading total on my iPod touch 4th generation before having to recharge, so this is a HUGE improvement.
EDIT: WiFi was ON during the test.