Not really, halo is a lot more indivdually skillful then cod4. Not to mention trying to block spawns is hard too.
Then there is sniping, which is a lot harder in halo to actually get a one hit kill. CoD4 there is no point to go for headshots, while halo rewards people for going for them and not going for an easier target (body)
Trust me, on a competivtive level, halo is A LOT harder. This is coming from a person whose played them both competitviely agaisnt top players.