My initial impressions of iOS 7 are extremely positive. The redesign works for me and I think it's quite beautiful (obviously, there are other opinions...). I'm liking all these little tweaks and my iPhone 4 almost seems faster.
(I had forgotten about FaceTime audio - basically, built-in free calls to iPhone users. That's a great addition.)
One thing I've noticed though: I cannot get a lock screen wallpaper to stick. Home screen ones work fine, but I get what almost looks like an enlarged, blurry version of the one I chose. Anyone else seeing this? Is it just an iPhone 4 thing?