im a huge halo fan and thats the game i put more time into but if i had to compare the two id say that cod has a better matchmaking system with people able to go in and out all the time. doesnt leave as much room for broken games such as halo. halo, someone on your team leaves and now your a man down and pissed about it. thats a huge turn off. i find halo requires more skill to take down your opponent rather than cod. cod you just put a couple bullets in their chest and thats it easy as pie. all in all halo wins for me but cod has its pros as well.