On my PC at least, its graphically better.. really noticeable when it goes to the streamed cut scenes. On 360 it looked like they were generated in game as they look the same, on PC the detail drops and the colours looked washed out. Its also smoother (again on MY pc, not neccesarily all), there was quite a few slow down points on 360.
And of course the mouse/keyboard combo, though i have made the point that it possibly makes it too easy to headshot all the time and they should have tweaked the difficulty up accordingly.
Downside... Dom is a fucking retard on the PC, took me ages to do the first berserker coz the twat kept getting stuck or dying.