Messages, Calendar, Calculator Photos, Clock, Maps, Notes, Reminders, Stocks, Passbook, Compass, Phone look better in iOS 7. Folders too.
Camera icon and Settings look 'dead', colouring in Weather and Mail look inside out, creating a 'dimple' effect and should be inverted. Videos looks too bright, Game Center looks weird and detached from the rest, Newsstand looks like Clip-art, iTunes and App stores' circles are way too big, creating a dominating effect over the other icons. Music app should stay plain orange. Safari icon should replace the white outline with a dark blue one.
The overall look of the icons is unpolished and inconsistent. By that I mean they should retouch all the icons so they all use the same sense of 'depth'. You know, like in iOS 6 all the icons seem to pop, in iOS 7 ALL the icons should look even.
The default background should be changed to a more discreet one, this one is too bright and totally lacks the 'premium' feel. iOS7 should ship with a nice landscape photo with good-looking mid-tones.
iOS 6 looks more solid but static. iOS 7 looks more dynamic but inconsistent.
I say don't worry, as this is an early beta and things will look a lot more consistent over time as the final release approaches - just like probably happened with iOS 1.
This is my opinion.
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Looks really great! It should me more in line with Apple's default icon set, though.