To be honest, I've so far only browsed the PHB. I was hoping for the same surprise that I got with Star Wars Saga Edition.
All the previews of Saga really turned me off, so I didn't think I'd buy it. My friend wanted me to pick him up a copy, and I paged through it and discovered a really great simplification of the 3.x d20 system.
Not so with 4e. They've changed so much of the fluff that you can't even call it D&D anymore. There were several minor changes that were not only unnecessary, but in fact broke something that worked fine to begin with. (what, only 5 alignment types?) Their reasoning behind chopping out half the deities, was that the list was overcrowded and fully alleged redundancies. But instead of merely trimming the list of some of the less popular/used deities, they chopped out more than half of 'em, including some very major ones, and replaced a handful with ones I've never even heard of!
Mechanically, I'm not sure if I like what they've done with the races and classes. I'm willing to give it a shot, but if my instincts are right I don't think I'll like it.
All in all I give it a 3/10.