Assetto Corsa - 10/10. this is the best pure driving simulator I've ever played. There's no hype, music, BS, just pure driving. The cars can be set up with varying degrees of control from full assists to stock configuration with full damage wear and no assists. I'm using a Logitech G25 wheel, playing out on a 2560x1440 monitor overclocked to 120hz with a core i7 3820, 16GB RAM and a Tri-x Radeon R9 290. This is the definitive driving simulator for PC in my opinion. I can't wait for Project C.A.R.S. It's got alot to live up to to come anywhere near this, especially in the handling.
I also really like how Assetto Corsa isn't fixated on one type of car, like many other racing simulators are. It has all kinds. Project C.A.R.S. will be more expansive, but less realistic most likely.