I usually use my PWTS, but I also have my G25 and use it from time to time.
Personally, I prefer the G25 with GT5. But for pedals I prefer the Fanatec Clubsports. If I want that, I have to use the PWTS wheel.
I find GT5 has some fairly diverse FFB effects, esp. on the kerbs. The G25 produces more effects than the PWTS seems to, but both are good with that game. For the Fanatec PWTS I set the FFB to 66, and I have the FFB in the game up above the default, but not max'd out. In that config, the PWTS's fan comes on after about 20 min of driving.
I am enjoying the SuperGT race cars (particularly the Lexus at the moment). I turn off all the aids, sometimes using just '1' on the Traction control on that car. Feels pretty 'right' to me (but what would I know about real SuperGT cars).
_________________________
Chunx