Well, I used the Pro Racer 2 for the PS2. Same concept, I guess, but I personally didn't like it. I found my left hand got tired very quickly trying to turn the car (tried with NFS: Hot Pursuit 2) and it took quite a bit of getting used to to do precision turns. However, it stressed my hand so much, I could really do only one race before plugging the normal controller back in.
I have one for the PS2 and the Xbox, it's really great for some games. I think the PS2 one works out better since the Xbox version's front triggers aren't nearly as good as the ones on the regular controllers.
Since a lot of PS2 racing games seem to be designed for the DualShock controller, full-sized steering wheels often don't work well (there's often a ton of dead-space in the center), unless the game has dedicated support for the Logitech wheel, the mini-wheel works out well as a replacement for the DualShock because it has a short 'throw' similar to the thumb sticks.
I haven't had the problem mentioned above by MarissaH with tiring hands, but everyone's hands are different, so YMMV.