Mmmm dat turn speed, seems completely unbalanced for twitch reflex games like CoD.
Watched a few clips of someone using XIM4 on Destiny on PS4, the turn speed and tracking was massively improved, I could see the auto aim screwing with his mouse aim, especially when the enemies were strafing, but still over all a much greater level of control.
The ability to turn 180 degree's in 0.1 of a second is something the controller just cannot match. If I was serious on PvP in Destiny and wanted that edge I'd certainly consider one, even still I'd like to play around on one just to see.