I've had several of the DFP wheels and currently am using the DFGT i think that the DFGT is a nice upgrade if you don't already have a functioning wheel. If you currently have a DFP that works, you will not be overwhelmed with the DFGT. The DFGT is a an improved version that is a little nicer and has some features that need Logitech to grow into. Both of these wheels work great with any pc or console that accepts the USB port.
I like lots of different racing games and can use either of these wheels on PC, PS2,PS3 or Xbox 360. The support for the wheels is more a function of the game software than anything else.Personally I like the DFGT better, but then the only reason I got it was that I had worn out my DFP's and needed a new wheel. having said that, I'd not buy another DFP as I feel that the extra money for the DFGT is a small increase for a nice, but not huge improvement in feel and features.