Ok, so now that I have had a chance to read a bit more of the book, I’ll touch on a couple of points of change.
The Skill list has been expanded and re-worked to run much more smoothly. You still get skill points based on your class and Intelligence. But, rather than having to figure out the costs for class/non-class skills, you pay the same for each, but class skills automatically get a +3 bonus to their use. This doesn’t stack for multi-class characters who have overlapping class skills. But, should you take a level in a class with a class skill you already have ranks in, you automatically get the bonus when you take the subsequent class. Additionally, when you level, instead of taking a class skill rank, you can opt to take an extra hit point. This is brilliant, IMHO, as it allows you to make a rogue or caster that is a little tougher than normal.
The Feat list has also been expanded, and fighters benefit from an expanded list of “combat feats” they can take for their bonus feats.
Speaking of fighters, there has been a lot of talk that this class suffers problems with inadequacy when compared to other, more ability-intensive classes. I just don’t see that. The fighter has several combat bonus abilities the other classes don’t have. Add that to the expanded feats, and the fighter can more than hold his own, and will no doubt be better equipped to fill his role in your party.
Experience is still not as simple as it was 2E and earlier, but it is clarified a bit more, and the book gives the DM more options on how to award it, and how to level characters.
All in all, my previous assessment that this is what 4E should have been may have been a bit premature. Pathfinder is still very much 3.5E. However, with the additions, clarifications and improvements, I think it’s safe to call it 3.75E. Or, maybe just Pathfinder.