I have a dfgt, am more than competent at driving (real cars), and I can say I really dislike drifting in gran turismo with the dfgt, as the motor is desperately slow. When you slide a real car, the wheel spins itself, if youre good you can just give the wheel a flick and catch it where you want to hold in countersteer. The dfgt has such a slow motor, you have to fight WITH the direction the motor is spinning, it feels like driving through glue lol. No good for drifting at all.
you can mod the dfgt to speed up the motor, and ive seen excellent results from guys doing this. But you could just as easily stuff it up and end up with a useless plastic box.
as far as im concerned, the dfgt is ridiculously cheap, is way better than ANYTHING even relatively close to its price, and is good enough for racing. I paid $130aud for mine brand new, modded the brake pedal spring to give it some resistence, and its good enough for me to be competitive online in races.
if you have the cash, and are really into drifting more than racing, buy the t300, as the motor is fast, smooth, and feels much more realistic to use as a consequence. For drifting, the t300 is the best ive used.