I really hadn't seen much about Pathfinder up until now, but I noticed quite a few people talking about it on ENWorld and saying some positive things about it, and that it fixed a lot of the issues of 3.5, so I figured I'd take a look.....
I thought 3e was rough to DM- I can't imagine running Pathfinder. The existing problems in 3e seem to have been magnified in Pathfinder, and casters would dominate even moreso than they do now in 3e. There are some cool ideas- the barbarian's alternative rage powers and the new cleric domains are both nice, but they are handled inelegantly and require a LOT of bookkeeping on the part of the player or (god forbid) the DM if he makes an NPC classed with levels.
For the most part, it looks like Paizo took all the things my group and I disliked about 3e (implied magic levels, rules interconnectedness, feats out the wazoo, magic item reliance, overpowered PCs, character building trumping actually playing the game, etc), and dialed them up to 11 (X-TREME RULEZ D&D!!!). Pathfinder is definitely a system for people who love system mastery and optomizing characters for the most effectiveness. For folks who love 3e, I guess thats a strength, but for me its a huge turn-off. Again, I don't know how Pathfinder would play, and I'd be willing to play a few sessions to see if it plays like it reads, but if it does, Paizo has lost all interest from me- which is a shame, because for the most part, I've really enjoyed what Paizo has done with their setting, the adventure paths, and the Classic Monsters Revised book.
It looks like Pathfinder tried to take some of 4e's ideas and shove them into 3.x, but its poorly executed and requires even MORE paperwork and prep time than 3.x!!! I know this is the Alpha release, and things likely will get changed some, but as it stands right now, I'd not consider Pathfinder a game I'd ever choose to play, let alone try to teach a new player. And without new blood coming in and expanding Pathfinder's fanbase, I can't see Paizo making this work long term.