There are two iPhone 5's in my house. One white and one black. Both loaded with iOS 7.
I have to say, I slightly prefer the white one for iOS 7. The whiteness of iOS 7 suits the white iPhone very well. It kind of feel sort of umm, uniform
Though there's one thing that can somewhat bother me on the white version sometimes. The super clear white of the body can sometimes make the white on the screen to look tinted yellow or blue or something. Depending on the light. If there's strong light on the body the white on the screen can appear a tad awkward. I find this is not the case for the black one. So the whites of the white iPhone can look a little bad at times. Like the white balance is off.
Though the overall sexyness of the white one kind of makes up for that minor annoyance. Today I kind of prefer the white one overall. Though iOS 7 looks great on the black one too.