See what happened with my 8GB 4G iPod Touch was it started to lag insanely at iOS 6 with the Internet shutting down for no good reason. I won this iPad 2 in a raffle and it was bought before the iOS 6 which had came out a month before, so I never updated my iPad 2.
Only bad thing on 5.1.1, is the YouTube links which takes you to YT preloaded app, which is so slow.