Got the playtest docs, going through it now. First impressions:
I love the modularity of themes and backgrounds, or at least how they appear to work going by the pregenerated characters (this doc has rules, monsters and scenarios but not character generation rules). That said, with the limited number of pregens here (5) I think it might be possible to extrapolate from these using the provided backgrounds and themes to make three or four more pregens going by these templates, as needed. The pregens do include level up notes to get players to third level for the playtest, which is good. They need a couple more pregens though for playtest groups with more than five players, though.
The first impression feel: kits are back
Monster stat blocks are smaller than they've been since the 1/2E days. And cleaner, more concise. Monster stat blocks are 20% stat and 80% cool stuff. Wow.
The mechanics are much simplified. The good bits of 4E (the really important bits, where unnecessarily complicated mechanics in 3rd were slimmed down) seems to have an effect on this rules, but otherwise the impression of 4E is nonexistent right now.
Spell blocks are more hermeneutic and descriptive than I've seen since 0E/1E days (but with more flavor). Seriously. The class traits which are like spells are treated here as being spells (like turn undead).
Rogues have schemes...interesting.
Fighter is the only one page character sheet.
Sample stat block from the modules include AC, HP, and weapons attacked with, nothing else.
That's it. Wow. There is a block of text afterwards that talks about kobolds, and what these kobolds are up to, but the actual combat mechanics are above.
This is definitely not 4E.
So right now, once they release the playtest char gen docs, I think I can safely say that I will never need to play Pathfinder or 4E again. Period. I seriously hope that the playtest serves to fine tune the mechanics but otherwise keeps what we're seeing here intact, because this really will be the last D&D I ever need.