The DF has a few advantages over other PS2 wheels.
It's cheap and good quality. It has large Dumbo-ear paddle shifters which are so handy, not the micro-switch paddles on the EX or Pro. I bought my third DF recently, brand new and in the original box - $25CDN delivered personally to my door. It doesn't have the quality feel of more expensive wheels, but it does its job like a trooper.
The button layout is the best of any PS2 wheel. The SONY buttons and D-pad are right where they should be. The top L and R buttons are able to be accidentally pressed when the wheel is turned fully, but that is rare.
There are a few problems with it, too. The pedals are not invincible, but they work well. The collar holding the steering shaft wears, but there are fixes for the looseness.
There is no better wheel for the money than a DF in good condition.
Cheers,
MasterGT