I'm disappointed with Apple at the minute.
I have 2 iphone 4s that's 2 x Iphone 4 lol not iphone 4S . . . .
Anyways they were both happily running along one on a really old school IOS 4.3 and the other IOS 6. something and they were fine.
I've upgraded them both to IOS 7 and they are both now extremely slow and laggy. I know the iPhone 4 is old hardware now, but they should advise that you don't upgrade past IOS 6 or something?
But seriously they are almost unusable now, even something simple like writing a txt message on both of them, your hitting the keys and you stop and it takes a good few seconds for it to catch up with what you have been typing!
I'm thinking of selling both of them and getting an S4
My step dad has the 4 and it is laggy from when I've used it. I don't get it as bad on my 4S but does lag spike and close apps. I don't think older devices will benefit from this update features wise apart from iOS in car.
Release Date: So it is rumoured that 7.1 will land on 15th of March which is a Saturday and Apple doesn't release public release updates on weekends so they may as well move the release to Monday or bring it on Friday.