The game itself, unchanged, still lacks a respectable plot and still has issues with combat (Being that combat is difficult, very limited and very frustrating). Many of the movement/climbing issues were resolved, with one minor exception, so the free-running experience is very solid. Time trials and speed runs are much more enjoyable on the PC platform as well, though the leaderboards are infested with cheaters already, something that should be expected.
In Strategy Informer's console review of Mirror's Edge, they said it wasn't really innovative. It isn't... on consoles. PC is a different story.