What Wheel?

[Zipppy]

My G25's wheel size is small compared to a real wheel, but still good enough. however, I think the G27's wheel is a bit larger.
The G27 is pretty good shall I say, and it depends on what you want really. The pedals on the G25 are robust, and I'm sure they're unchanged on the successor. The shifter on the G27 is improved over the G25 as well.

I've had my G25 since 2008, and I still like it a lot, without any issues other than one of the wheel buttons being wonky after aggressively pressing on it in Burnout Paradise once.

I'd say the T500RS is more PS3 oriented for GT5 though, but I haven't tried it. It's quite expensive compared to the G27.