I play both Pathfinder and 4E, so perhaps I should not comment because I don't fit the criteria. But here are things that pop into my head while playing Pathfinder (and these are things that people who love 3.x/pathfinder probably will not agree with me on):
1. No Iterative attacks. It really gets tough at higher levels in 3.x, when you have 3 or 4 attack rolls, each of them doing x damage dice for the melee fighters, but the wizard still gets one attack spell to cast. So the fighter takes 3 attack rolls, plus adding all those damage dice up, and the wizard casts a spell, misses the spell penetration roll and is done for another 5 minutes. So the removal of iterative attacks, everything standardized to various action types uniformly gives everyone at the table the same amount of time to work. Everything is balanced, and it's clear what actions are on which steps. Instead of iterative attacks, the damage is upped.
2. Attacks versus defenses - All of the attacks are made in a similar fashion, regardless of what sort of attack they are. There is no saving throws made to avoid the effects of a spell, it was my die roll as a spell caster that makes things happen, not the DM rolling for the monster. That is more exciting to me as a player than saying "I cast fireball into the room here, and it does X damage, half if they save".
3. Action Points for an extra standard action. I love this, it makes the chance to be really heroic happen once in a while. I really miss those when playing Pathfinder.
4. Uniformity of spells / powers - Everything is in a standardized format, so it's easy to comprehend the abilities of a fighter or a wizard because the information is in the same location. When I play melee types in Pathfinder, I find it limiting in terms of what attack options I have are. When I play a spell caster in Pathfinder, I find I am spending my time between turns looking up spells and what they do and how they work.
