I don't have a ps3, or a xbox360, however i have spent quite a bit of time playing both of them at friend's houses. I personally think Killing Floor would do very well at a cheap enough price, like the same amount we paid on steam.
The controllers would be fine. I personally don't do that well with a controller in a FPS, since I'm so used to mouse/keyboard for years on end. However, my buddy who doesn't use a computer for games, but instead his ps3, does very well with the controller in games like CoD5. Hardcore mode in that game has no crosshairs, but does have ironsights just like killing floor, and it's still very playable.
I really don't think Killing Floor would have much of a problem.
What'd be interested is if games on PS3, and X360 could be played with PC gamers. Obviously the PC gamers would have a huge advantage, but if it's a team game, it wouldn't matter as much. It WOULD be nice to have the option to switch between a server that is open to all players, versus a server that is limited to a specific platform. It would definitely add new life to the servers if you could integrate 3 platforms for one game.