Can i ask something about it?
What kind of people use a controller in a FPS game?
I'll tell you some argument to don't use a controller on a FPS on a computer....:
- Shitty AIM because there is'nt an aim helper like mostly FPS such as CoD on PS3/XBox ...
- shitty reaction delay because of the sensibility.... or shitty aim because of the sensibility (if this last is too low or too high) the good balance doesn't exist with a controller.
- too few keybinding possible so you get too many combination of keys.
So..... for you own sake just buy a good mouse and try the best way of playing a FPS.... Mouse and keyboard....
Or....wait and see if they choose to allow you to use and customize the settings of your XBox controller....