i tried both logitech and ps3 controller, and also the microsoft xbox 360 controller using the usb wireless receiver. sadly, the microsoft wireless receiver is not supported by the mac, and the 360 controller wouldn't bind to it.
firstly, i tried the ps3 controller using the the bluetooth connection since this is the most cleanest arrangement. the ps3 game pad steering controls feel smooth and i used the buttons for the throttle and brakes since i'm a thumber. i played around with the trigger for the steering and brakes but did not give it much thought on the proportionality of the control since i did not feel comfortable playing racing games this way. during the selection menu the directional pad and the left stick act as a mouse input and the action buttons act as the back and select buttons.
the logitech rumble pad 2 has a similar steer feeling like the ps3, or perhaps a better feeling than the ps3. maybe its because the heft and robust built of the gamepad give it this precision feel. the problem is the throttle and brake buttons on the logitech are in a backward arrangement compared to the ps3 controller. and since the buttons are not customizable in the game, you wil use have to live with it if you want to use the logitech gamepad. the pause button are also weird as well. basically the throttle, brake, pause, back button are all mapped wrong on the logitech game pad.
perhaps an option to customize buttons mapping would be better.
the ps3 controller is by far probably the cleanest arrangement for this game in my opinion. with bluetooth enable it quickly binds to the game pad and stays connected.
cheers folks