You know, it never fails to amaze me, the MacRumors definition of perfect when it comes to game framerate and playability. Why is it that people seem so determined to use that word, "perfect"? I have the new 2.4 MBP and I can't run World of Warcraft "perfectly". Don't get me wrong, this machine is excellent and plays that game really really well (steady ~100fps in old areas, ~60fps in outland). But that's not 'perfect'. It stutters heavily when loading things from the disc (as it should considering it has a 5400rpm drive). I would be shocked if this machine could play AC 'perfectly'. Not to mention, the act of reducing graphical settings takes it out of the 'perfect' category.
In my experience the XBox 360 version of this game is excellent, though the game itself has some flaws. Please refrain from using this term 'perfect' unless it runs as well and looks as good as the 360 version (or PS3 for that matter, though my experience there is only based on HD vids that I've seen).
That said, I would give it a try. It will probably be a bearable experience if you don't have a 360 or PS3, but don't overestimate your machine. They're great, but physics only allows for so much power in such a package at this point in time.