Both have terrible campaigns, though at least I didn't beat black ops's in about 2 hours without trying to do a speed run. Can't say the same about mw2.
Very few of the spec ops missions in mw2 were good while zombies in black ops is a fun game and dead ops is awsome as well. Pretty sad when a minigame is more fun than the campaign though.
Both have pretty terrible multiplayers that are way too easy, but black ops is slightly better balanced and not as god damn easy to go 32/2 every single game.
Overall both games suck if you play them for the campaign and multiplayer but black ops includes the awsome dead ops and zombie mode to make it worth it.