@Controllers : Most PS3 players will cream the PC players i've played against (gotta say that maybe the aiming response time is better, but with the players camping most of the time, they don't get to practice the other critical aspects of a competitive FPS like strategic loadouts (weapon and eqiupment), strategic movement through the map, controlling an area, building on team play...
@Gameplay : I'm sorry if i'm generalising too mcuh here, but there are just so many cheaters, campers, noobers, hackers (including the directx hacks) that it's just not fun, so when the gameplay is reduced to a slower pace than wii bowling, then i couldn't care about the controllers or graphics...it's just *NOT* fun !
@Graphics : Definitely PC trumps console, provided your pc can handle it (and it should), i have a 3gh core duo with 8800gt and 2gb mem and it runs perfectly....it's definitely nicer playing with higher res. graphics...
@Price : (only cos it was mentioned), PS3 trumps PC...it's sligthly more expensive, but don't have to deal with steam, you can re-sell and it holds very good re-sale value because it's on the bd format (scratch resistant)...
FINAL DECISION
If you going to be playing ONLINE - PS3 (NO DOUBT)
If you going to be playing offline - Tough choice ..PC for graphics (maybe controllers depending which you more comfortable with) or console for being able to lounge on a couch while waging war and the fact that you can actually sell the game after you complete the 6 hour campaign!