I've been using the standard Sony controller for a long time now, I've also used the standard PS2 controller with a ps3 adapter attached to it and it works great as well, I bought another controller (don't remember the name) but it has a big battery on the back so I can't hold it the way I want to, in my opinion the regular Sony ones are the best ps3 controllers, and if you want more accuracy you could try out Kontrolfreeks (make your sticks longer, I never used them but I heard good stories about them). I don't have any experience with mouse / keyboard on ps3 sorry.
I use a standard controller and use control freaks, they are like $10 oen the internet and they extend the sticks about 1cm and help so much. It takes about 3 games to get used to and when u go back to regular it is wierd but they help so much. I noticed a kd increase and everything, it helps you turn quicker and lock on faster, I win basically every gun fight and I use hadline, not quick draw!