For some users iOS 5 proved to be the main enemy of the battery autonomy. iOS 5.0.1 solved the problem for some users but for others Apple was forced to admit the second time that launched a version of iOS with problems and now is working on iOS 5.1.
iOS 5.1 beta 2 was released this week and it is expected to solve all the problems with the life battery, the solution could reach soon. Meanwhile an Italian forum made a small battery test on the iOS 5.1 beta 2 and they found that compared to iOS 5.0.1 there is a marginally improved autonomy.
We talk about a few extra minutes of usage for an iPhone 4S but they say that Apple keep open processes in beta versions, processes that improve the battery autonomy. In my experience, what you find in beta verison, you will find in the final version and the battery life has not improved, in my case, at the transition from beta to a final version.
I can say that in all versions of iOS 5.0.1 beta for iPhone 4S I get over 6 hours of usage on making any on the device but to be honest I do not think that I’ll obtain the same thing from any version of iOS 5.x.