I'm making this a separate post in case the Admins need to delete it.
The OP said he needs iOS5. He could be a dev and is asking about the battery life before taking the plunge. I've also got a personal opinion on whether he's a dev or not, but staying on topic is a good thing. If the OP paid his $99 then he knows the rules. If he's going to go torrent it or pick it up some other way, then I don't think he's going to listen. Personally (again) I'm not a dev and I would love to try the new stuff but I'm not going to put a beta on my daily use phone.