I'm seeing an increase in battery life until today when my iPhone went from 92% to 20% in three hours and the phone wasn't in use. Pretty sure it's some bug in iOS other than that my 4 lasts an entire 24 hours and still has 40% of battery life now. That's with listening to music, internet over 3G, internet over Wi-Fi, making phone calls, apps, and standby. Much better then previous in iOS5.