Rene Ritchie:

The physics is one thing, but it goes beyond that as well. Where everything in iPhone OS 1 to iOS 6 looked rendered, everything on iOS 7 looks on-the-fly. Animation, interaction, color, type, control, everything. To beat the irony out of a dead horse, Apple has made iOS dynamic. They’ve made it come alive.

The more you use iOS 7 the more this is on display. Android users will likely point to the fact that their OS has had dynamic backgrounds for quite a while, but there is a vast difference between a background that moves (and for me, distracts — I don’t use dynamic backgrounds in iOS 7 and don’t think I ever will) and getting the whole OS to move in a way that makes more sense.

Slide to unlock still needs an arrow, though.