the question is NOT what you think about using the 360 controller on a FPS... the keyboard mouse is always better... move along...  
 
Assuming there isn't a problem with the controller working...  playable with the controller?  
some games you need fine control and others you don't. for example, fallout3 and boardlands work fine with the controller. I didn't feel like i didn't have enough control to shoot stuff.. But left for dead or AvP (ugh.. bad).. i couldn't hit shit and I wouldn't suggest using it for those games. 
 
CLEARLY you console ppl use controllers for all these games and you mastered it. I'm not talking to you :) I'm not so good with the controller for fps, but i do like playing from my sofa and a 63" HDTV @ 1080p with AA and AF max'd. 
So will someone that is "OK" with the 360 game pad have fun with the game? 
 
this is for single player only. For mutli i'm going back to my main box and k/m/2560x1600 ^_^

Let me direct you to somewhere you might feel at home. 
 
http://www.reddit.com/r/circlejerk    

it's fine, the interface is basically like call of duty on the xbox when you enable the controller.

Resurrecting dead thread to just say that it sucks..... it's floaty and crap, makes me feel like i have no choice but to try and get the hang of M&B (which i heard somewhere, is better).
I did get a Huey with the controller on PC and just killing anyone is satisfying knowing that you defied the odds.... but over all it's not worth it.  It's not a case though of it being unsuited, i finished Borderlands with a controller on PC, it just feels like it's tacked on and unfunctional....like a built in xpadder is working away in the background, which is odd since they clearly worked it out on the XBOX with no problems.