Playing exclusively (online) on my PC, I can honestly say that I just don't have the reaction time to compete in the fast-paced FPS games.
Once I spot an opponent and my brain has finished loading the Point 'n' Click routines, I stand a 60% chance of being dead, and a 40% chance of the other dude being slower then I am.
When I actually get the mouse moving, I'm deadly accurate, and I'm also the type of gamer who buys the good hardware, and know how to combine mouse/pad and the like.
I've always been much better a large-scale shooters like Battlefield (Not this Bad Company atrocity) and ArmA 2, where situational awareness is king, and which strive to be a tad bit more realistic than your conventional CoD / MoH / BC generic-brown-shooter-deal.
That's not to say that I don't fancy the brown shooters though, when I just wanna shoot some guns by myself.
My K/D is usually hovering around 1.20-1.45, to some extent because I get lucky with my Killstreaks/CarePacks, or put distance between myself and the enemy by use of a high-powered scope and a .308+ bullet.
I never survive long as a Sniper though, 'cus once again, I'm too used to playing games that don't sport KillCams and where I can actually shoot from a full 500 yards or more, as opposed to covering narrow sniping lanes at a max range of 70 meters.
As to whether I'm a sore loser. Nah. I just shake it off and go back at it. Sure, if I get a 'Nade launcher to the face, or some guy pops me with the AK47u Rapid Fire in Black Ops, I'll get a little annoyed, but then I remember that the newbies gotta have a way to compete as well, and just keep playing.