People still talk about iOS 5 having worse battery life. And GM is pretty much a finished product.
Judging by YOUR logic though, that shouldn't matter since it is still in BETA.
GM is still not the RC. They are STILL unable to talk about the product; they can't say anything that Apple hasn't released publicly.
Informing us that people are breaking the NDA doesn't prove any point whatsoever. I'm just letting you know why nobody is talking. Breaking the NDA and getting caught can, well, put you in jail. Either that or some VERY hefty fines, whatever is drawn out in the contract.
You would be alright inferring that iOS5 would use more battery power anyway, finally pulling in and aggregating notifications along with the many other features is obviously going to have an effect. I, of course, didn't make this assumption though as it would be ignorant to; software is always being refined to be more efficient.