I found it amazing, and I found Killzone 2 amazing. The thing about MW2 is it just doesn't really let go, which is not always that great, as Uncharted 2 has its pacing nailed because it has the more relaxing periods. In MW2 you're not that surprised when you get another 60 guys coming at you, because you have just killed another lot, so there is still room for improvement in SP
MP is great, I don't like the maps as much as the first, but rumours are there is a MW 1 map pack coming, so I am looking forward to that