Treyarch & Infinity Ward, which one makes the better Call of Dutys?

To me, I think Treyarch does far more interesting things with the COD franchise. Things like Zombies, Wager Matches, and the soon to come branching storylines and strike force missions in Blops2 just show me that Treyarch is actually interested in doing new and interesting things with COD. Infinity Ward on the other hand have made little to no changes to the Modern Warfare formula. Sure they've improved, but the games just aren't impressive anymore. What do you think?