That's quite interesting! It's okay on a black iPhone I have one myself but the white on white iPhone definitely looks better. It makes more sense from a design standpoint as well.
I'm curious to see the possibility of a black on black version of iOS 7.
Moreover, you guys know how when you're using a navigation app at night, the UI and maps change to a dark color scheme?
I use iOS during the day of course, but I like to end my evening checking my YouTube subscriptions, under a dimmed night light. Wouldn't it be great to have time-specific UI colorization?