User blog comment:N7/Battle of the First Person Shooters - Halo: Reach vs Call of Duty: Black Ops/@comment-1427137-20100802135228

Well, MW2 had a lot of new content in it. New engine, new weapons, new perks, new mechanics. It was the same kind of game as CoD4, just a lot of new things in there.

BFBC2 didn't have so much new content. All the weapons are the same except for a few new pistols and rifles. The vehicles were all the same except for the Quad Bike and Personnal Watercraft. Yeah they put in specilaizations and updated their engine, but most of the work had been done before BFBC2 was even being made.