I've been getting poor battery life with beta 4 on my iPhone 4, and iPad (3). However, I haven't set either of them up as new since iOS 5. So I'm probably shooting myself in the foot there.
Regarding poor battery life. I know multiple people who get incredibly poor battery life on their iPhones without using them much. Two of them are on sprint and are often in poor coverage areas. I should also mention that my AT&T coverage at home is really poor and it definitely impacts my battery life compared to what I see at work. Anyway, my point is longevity off charger will always vary greatly from user to user and sometimes from variables outside of their control.
Regarding poor battery life. I know multiple people who get incredibly poor battery life on their iPhones without using them much. Two of them are on sprint and are often in poor coverage areas. I should also mention that my AT&T coverage at home is really poor and it definitely impacts my battery life compared to what I see at work. Anyway, my point is longevity off charger will always vary greatly from user to user and sometimes from variables outside of their control.