It's what D&D 4.0 should have been, IMO. Better rules for the skills, combat maneuvers, more balanced classes (though not perfectly, but better) and a lot more freedom when it comes to character creation. I like how so much variation is available within the individual classes, that it means you can build very different characters from the same base class without multiclassing. In 3.5, if someone said they had a lvl 5 rogue or a lvl 9 sorcerer and were playing core only, you could probably guess what they were bringing to the table. Not with Pathfinder. Makes unique characters easy to create, and having all of their content free online is just the cherry on the cake. Loving it as much as we do, most of the people in our group have bought the books anyway, but it's great to be able to look up a rule or class feature in full on the fly.