What 4th Edition should have been:
http://paizo.com/pathfinderRPG/prd/
Anyway, I've played one short 2nd Ed. adventure, which ended quickly due to a hail of goblin spears on our 1st level group. What really got me into D&D was 3rd Ed. though. One of my friends was obsessed enough with D&D to buy EVERY 3rd Ed. book, and do all our DMing. Quite frankly, all the supplemental material for 3rd and 3.5 is overwhelming, not to mention the base classes are rather bland compared to the PrCs. This is where Pathfinder saves the day, in my opinion. With Pathfinder, all the base classes and PC races have been vastly improved with new abilities and features. For once, taking base classes to level 20 is actually a VERY GOOD IDEA, due to the fact that you'll gain useful abliitis and improvements the entire way, and a very worthy set of ablities at level 20. The 3rd Ed. practice of dipping a few levels into other classes just to gain certain feats or abilities, and juggling multiple PrCs was too ridiculous. Furthermore, certain mechanics like the skill system and combat maneuvers have been made simpler.
Anyway, no, I haven't played 4th Ed. However, based on everything I've read and heard, it seems like 4th Ed has turned the ruleset into that of a MMOG. Massive simplification and homogenization is the impression I walked away with after reading about 4th Ed.. Every class has a built in "healing" ability, and many classes have similar damage outputs that differ only in the type of damage dealt, or the weapon used. Certain combat maneuvers can only be used "once per encouter" even though it makes little sense in a realistic way. I recall reading something like "Fighters can only use bullrush (or maybe it was called "knockdown"?) once per encounter". Why is that? Certainly not because it's realistic. Heck, why CAN'T some big burly guy who's good at rushing and tackling do that more than once in a fight? It's not for realism's sake, it's for the sake of an abstract "balance" between all the classes with respect to their combat performance. I see 4th Ed. as a bid to draw in today's youth who are familiar with simpler game mechanics and MMOGs, and not with D&D prior to 4th Ed.
That's my two cents.