I have just beaten the game a few days ago. 30% of the game took me 30 hours of lots of fun. Even if what people are saying is true and the game does get a little repetitive at a certain point (which I still haven't reached), I can assure you the game provides with some extremely exciting first 30 hours.
And as I am having so much fun with this game I was considering to promote it a little bit through a thread, so here I am, supporting the OP.
And eventhough I loved Final Fantasy XIII and was one of my favourite games of last year (way behind Mass Effect 2, RDR, SMG 2 and DKCR if you were wondering) I can see clearly as day why you are saying this was SE best game of the year.
It was, by all means, my sleeper hit of 2010. I wouldn't dare to go back to InFamous now. I had to force me to play that game and I never really had much fun. After Just Cause 2, it looks even more boring.