Hello. I've just set up some official configurations for Steam Controllers.
The default one makes the controller work a lot like a traditional controller, but with a couple of added extras like using the rear grip buttons to enter vehicles and change weapons so that you don't have to take your thumb off the aiming pad.
One of the great features of the Steam Controller is that the pads are accurate enough that you can use them to control a pointer, and that's what the second 'Mouse Style' configuration option does. It allows for some very precise aiming. It definitely feels different and it might be my new favorite way of playing the game.
If you don't have a Steam Controller yet here's a screenshot of the screen where you can change configurations.
I'd be very interested to hear what you think when you've given them a go, and if you make a cool configuration yourself then please post it publicly and let me know so I can give it a try! :)