I like Treyarch because they have zombies, more customization, and better ranking system. I hate how every time infinityward makes a new game, they have to increase the levels to prestige, i preferably like it more with lower rank and more prestiges. Treyarch also have more customization. In black ops, you were able to customize your emblem, more reticules, Reticule colors, clan tag color, etc. The Ranking system is cooler, i liked having to use cod points to buy things, that way if someone was a higher rank than you, you could have a even match with them class wise.