I'm more of a console gamer than a PC gamer. And since getting my first gaming PC for a loooong time last week i've been reminded why. Nothing but unexplainable crashes in SCII.
But any, that's besides the point. I've played many FPS games on consoles and the response is perfectly fine. I just don't see this huge difference everyone goes on about. It is there for sure, I don't find it anywhere near as significant as others seem to for some reason.
In my experience, it is probably more difficult to go from mouse to controller than the other way around. You should be able to get used to the PC controls in 15 minutes.
I've been using a playstation pad since 1995 or 1996 whenever the PS1 came out so I guess that's why I don't find as big a difference, the controller in my hand becomes more of an extension of my brain than something i'm holding - in that i'm so used to it that the response is instant. Completely unlike the Xbox 360 pad, where my response is slower to the point where I thought it was the console being slower than the PS3.
I also always turn aim assist off.
I find the difference far more significant in RTS games. These are simply unplayable on console for me.
Now that's out the way, i'm now going to praise the PC side of things over the consoles. And that's when it comes to party/clan games, community, voice chat etc.
The PS3 in particular is terrible for this and the reason I purchased an Xbox 360 in preperation for playing BF3 with friends. I've had so many issues on PS3 trying to party up with friends, the invites simply never work. And when you get in a game the headset noise is often so scrambled you can't hear anything.
The PS3 is my most used system, and will stay so but NOT for multiplayer games.
If you want more chat, have games with friends, or join a community to play regular games with people. Especially in BF3 where creating a squad with regular people could add so much more to the game.
I'm going down the Xbox route. 2-3 of friends don't have gaming PCs so we are all going down that route to play together. Unforunately for me, the Xbox is my worst gaming device for controls!! Damn.