Blah! More intermittent random connection problems. Cant really get an online match going right now. It has nothing to do with routers or 360 setting tho, cos whenever I do manage to get into a lobby, everyone is complaining of these problems. I expect an update for this game very soon.
Now as far as comparing Halo3 and CoD4, well imho, the options of Halo 3 are superior. Forge, Theater, custom gametypes, etc are all incredible.
But once you get down to the actual meat of the online game, the actual action, I like CoD4 better. I think CoD's gameplay with all the Halo 3 trimmings would be the greatest online shooter ever.
Play some CoD for a while, then go play Halo 3. You feel like your running and jumping in slooooooow motion. lol Its still great fun, it just feels soo different. Like someone else said earlier, they are both good games, both worth owining and playing online.