Is will be very slow to update iPhone 4 to iOS 6.0.1?
Actually I just asked someone who updates iPhone 4 to iOS 6.1.2. After updating, it’s ok for common operations, but if want to run large programs, of course it is very slow, but acceptable still. It is not that serious like can’t stand the speed.
Fluency of iOS 6 and iOS 5 is almost the same, I think. The new version is not that smooth like old one, but it has more functions, of course.