I bought this yesterday and was quite impressed.
Given I can't play GTA4 because I don't have a Quad and a graphics card newer than a year, I was pleased this ran well!
I ran it in all max settings for the max res my monitor supports which is pretty much my LFD settings and it works great! I'd say at least 30-40fps constantly, which is enough!
The game itself is great fun. Lacking if being compared to GTA4, but the differences (Parkour, Movement across map) is truely amazing and good fun. I'm using K&M and it's fine for controls, I'm used to playing that way as a through-and-through PC gamer so no issues there.
Played a few missions so far and pretty much upgraded all my movement abilities. You get to play the fully powered up guy and then the story regresses to the start and you had less power. First thing I noticed was "why can't I move like a legend?" - then I realised I had to upgrade and you had to get around a lot...so it seemed natural to do movement first. The guy kicks enough backside to not worry about "Combat" upgrades for a few missions at least
In general, good game, it's something other than FPS that I will find myself going back to for a random go on. I will complete it but by playing it slowly, maybe an hour at a time.
Better than Wolverine, imo.