Neither. To be honest, while the original games in their respective series (I mean, starting with CoD4 on the Call of Duty side...the other three before that sucked.) did a lot for the genre of first person shooters, since then, neither has really evolved into something different. They're both cookie cutter, lackluster FPS games, except one is slow and in space and the other is too fast and on the ground.
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Therefore, my answer is:
Team Fortress 2!
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Do you also lack the Delta Brain Wave?
OT: What the **** did I just watch? I...I'm scarred for life.