Originally Posted by M1sT3rM4n
I have an iPhone 4 GSM model. iOS 7 on it performs only fair. You will notice significant lagging when switching from apps back to the home screen. The overall design feels too similar to Windows 8/Android for me so I reverted back to 6.1.3 using iTunes.
Yeah performance hit is quite unreal. But I want the aesthetics enough to stick with it, albeit the older devices (iPhone 4, even iPad 2) got a lot of features nerfs. For example, no colouration or blur on the new control centre. Sigh.
I hear on this thread performance has shown to be taken hits on the iPhone 5 too. I call poor optimization and the iOS 7 was rushed for release as a whole.