It pretty amazing, I never expected Assassin's Creed to do this well. Good for Ubisoft. It really was a technically impressive game with the climbing, though I didn't play it too long.
I am pretty SMG may have longer legs though; not because I think it is better (which I do, but my opinion is irrelevant). SMG will stay up there longer because there are fewer "AAA" titles on Wii for the "hardcore". I don't mean this to knock either game or any platform.
I would cite regulation, but I know you will simply ignore it.