I'm not having the issues except for the fluctuating mouse sensitivity which isn't that bad.
First thing I did after I installed the game was crack it with skid..row because I have a solid aversion for steam f'ing up my immersion in singleplayer games and the fact steam f'ed up my AvP performance.
Who knows.. But if your game is ridden with crashes and slowdowns... Give a fixed exe a try.
Playing: Skyrim, World of Warcraft.
Future: Dead Space 3.