I was absolutely blown away by just how good Forza 5 looks. None of the videos I have seen do it justice, and there is no racing game which can compare with its visuals. When you see it in 1080p at 60 frames per second, it's just breathtaking.
However... I got about 4 minutes of gameplay in the McLaren P1 using the prototype Thrustmaster wheel, and was disappointed. It's hard to say or know if it was this wheel or the game's physics, but the car felt "floaty" and somewhat disconnected from the road. I got a bit of oversteer and understeer, but there was no real sense of what the car's tires or suspension were doing. All aids were off (with the exception of driving line and traction control, which was its lowest setting), but it wasn't a very rewarding driving experience.
Hopefully this is something that will change or improve, because otherwise the game looks stunning.