I'm a little flustered about the whole thing. I might be a little spoiled about playtests, but this one was just kind of... Eh. You've only got materials up to level 3, the characters are pre-gens with precious little (or no?) customization, and some of the rules seem abbreviated. (I did a moderately thorough reading, although I did skim parts - were there ever actually rules for skills outside of the charsheets?) I'm not even going to dwell on the absolute nonsense they've gone through to try and keep people from redistributing their stuff, despite saying we can discuss it openly.
I am rather pleasantly surprised, though, how it seems much more 3rd Edition than 4th Edition. I can't really find much wrong with the rules themselves. I like the idea of Advantages and Disadvantages (which is essentially 'roll 2d20; take the higher/lower of the two rolls'), since it's more interesting than a simple modifier. Not sure if it's that balanced mechanically, but eh. Spellcasting is back to Vancian, for better or worse.
I'm actually a little confused as to how spell preparation works - wizards seem to be exactly like 3rd Edition (prepare exactly the spells you want; cross out each as you cast it). Both clerics have only 2 spells per day and three spells listed as prepared; either there's a typo on both sheets, or clerics prepare a certain number of spells and then can use their spells per day as 'MP', ala Final Fantasy 1. Spells also seem to have absolutely no scaling beyond your ability modifier - except magic missile, which is now a cantrip (which are essentially at-will powers now). For example, Burning Hands always does 2d4+INT damage and that's it, saves excepted.
Everything also seems very streamlined - basically everything now is flat-out an ability check. It's pretty clear they're catering to the old school crowd (what with 10 foot poles and the adventure being Keep on the Borderlands). Honestly, I wouldn't be surprised if this was someone's rules-lite hack of D&D. I was glad to see the ridiculous rules for surprise rounds from 3e have been replaced with a huge penalty to the surprised side's initiative checks, ranged attacks being simply 'normal within this range, at a disadvantage at long range', and several other simplifications that make good sense.
Oh, and a couple of nuts things; the rogue can never roll under 10 on skills he's trained in, and the healing cleric just kind of says 'screw it' to ever rolling for healing (he automatically rolls maximum) when he hits 3rd.
I guess the TL;DR version here is that I'm tentatively interested by all the little changes I can see, but I would appreciate having had an actual core rulebook's worth of rules rather than a How to Play and some pregens slapped on me. Like I said, maybe I was spoiled by the Pathfinder Beta, but I'd at least liked to have some character creation stuff (the character sheets provide just enough to get me interested). Also, spells scaling at all.
The bitter cynic in me also has a purely knee-jerk reaction of 'You guys DO realize the old school market is already playing Pathfinder/1e/2e/Labyrinth Lord/like, a billion other things?'