I am thinking of buying this game, I've only got a PC, so is keyboard+mouse working 100%, or should I buy an Xbox controller?
I would argue that it plays better on keyboard+mouse, your powers seem to be (for the most part) aim-based....like blink it gives you a circle of light showing you where you will blink to and you aim that using the mouse (on a console by using the same joystick that you look around with). That specific power is 10x better when you can use it rapidly. I have been abusing it to escape enemies when I am detected, and without lots of time playing consoles I know I couldn't use it nearly as easily as I do with a mouse.
I suppose if you suck with keyboard+mouse but are good with controllers, then a controller is the way to go, but as a PC gamer (mostly), keyboard+mouse feels a lot better, at least for some specific actions, in this game.