PROTIP: if you download a developer preview of iOS 7 (and this might apply when they release to everyone) take screenshots of your homescreen(s) (home button + power button), if you're one of those people who likes having their icons in certain places... the install doesn't preserve those very well.
So yeah, I used my developer license to become an early adopter of this. (Here's a decent rundown of many of the changes) It's clearly still a work in progress, but not bad over all. The glamour feature where the background behind screens moves independently, give an illusion of depth, is really clever. I mean, even the SNES could do that kind of parallax scrolling, but it was smart to put it in there.