The new squadmate-specific combat interface and mouse-centric UI are a joy to use, and the story is theatrical and compelling, with a galaxy worth of content stuffed into one hell of game. If you've already tackled the console version, you certainly don't need to shell out for the PC version, too, but if you haven't yet experienced this magnum opus, this is the version you should play.
PROS: Eliminates most of the major problems of the 360 version; gameplay is just as good.
CONS: Has minor problems of its own that keep it from being just about perfect. 4.5/5