Well, I can answer that with just my K/D on the three most recent Call of Duty games.
My Black Ops K/D is 1.22. This was when I used an XB500 for gaming, and the fact that Black Ops 1 has awful sound for tactical purposes.
My MW3 FFA (my main game mode) K/D is 2.67. This is when I got my HD598 and my Q701, and the fact that noises on MW3 are super loud. SitRep Pro is almost a game-breaker if you're good at tracking footsteps.
My Black Ops K/D is 1.33. The sound on this game is terrible. It's so bad that I refuse to play it and I just sold it over eBay yesterday. This is despite having even better equipment than when I played MW3.
Edited by Tus-Chan - 12/14/12 at 6:22am