I have the X4's and the Tritton 720 set. I like the Tritton because it is wired, doesn't use batteries, but the cords can become a pain sometimes. The X4's have become useless since I bought my plasma TV as the IR signal gets interrupted by the white noise of the plasma, but being wireless and having a mute button on the controller is another feature I wish the Tritton headset had. The X41's are RF, which eliminates the white noise problem, so I'd like those, but I'm sticking with my Tritton's right now because I don't feel like dropping another 200 bones on another set of headphones. If I buy an LCD or LED TV that shouldn't be a problem anymore and the X4's will be just fine.
Headphones are a MUST on Search & Destroy in MW or MW2, especially on defense or if you are the last man standing on offense.
P.S. My X4's are brand new, as the old ones crapped out and they sent me a brand new pair to replace them in the 11th month of a one year warranty - nice!