Been having a play with someone's phone this afternoon and, whilst some elements of the new interface are quite nice, they've really hit this with the ugly stick, haven't they?
The month view on Calendar has been broken so you now can't see what you're doing on a specific day without going to day view, the 'tap to top' on Safari is hit and miss at best it seems, and don't even get me started on the 'flying' icons every time you unlock!
The new mail and messaging interface is nice, but I'm not sure they're enough to get me to switch lock stock to iOS7 just yet.