There’s a lot to love about all of them (except the edition after 3.5e and before 5e that shall not be named nor acknowledged), but I prefer the Pathfinder rule set. They fixed much of what was wrong with 3.5e and added a few new twists that restore a lot of the joy of playing that had been diminished for a while. Yes, Pathfinder is a bit math heavy at times, especially when trying to figure out if bonuses stack, but I think it rarely causes the game to get bogged down and it adds a lot to the playability over 3/3.5e.