Was I wild about 3.5? No.
Did I buy the core books again? Yes.
Did I do it because I thought the rules needed an overhaul? No.
I did it because my old Core books (bought as soon as humanly possible) were falling apart, and I figured I might as well get the gift box with all three.
Here's a run down of what I think of it...
Pros: Fixed my issues with the ranger, greater weapon focus (because eventually a fighter would run out of feats to be a bad ass with just one weapon), fixed a few problem spells, and the crowning achievement they finally made damage reduction perfect.
Cons: Gave WotC an excuse to rehash everything again! I will never be convinced that the Weapon Size rules are anything but utter idiocy... I still use the 3.0 rules they make more sense to me. Buff spells got nerfed horriblly... 1 round/level is great if all you ever do is fight, but if you need to lift a portcullis 30 seconds isn't going to cut it. That being said 1 mintue/ Level is still better by me. Same could be said of invisiblity spells. Also boosting DC... am I alone in missing this? I'd complain about square spaces too, but I don't play with minis, in fact I intensely dislike them.
What do I give 3.5 on a scale of 1-10 (when comparing it to 3.0)? 6... it made some good changes but it wanted too much to be a minature game.