From the OP which is what everyone is going by, GT5 wins for me for both control and game play as I want a driving sim and not a arcade racer. Nothing wrong with arcade just I don't want this in a sim. Hyruken claims Forza can be as realistic yet this is not noted in the OP.
P.S I even used those "realistic tires" in GT series before so even in GT series they made tires stick to the road a lot better than in RL (except the realistic ones).