I have one of these in my GT4 cockpit setup (the old 100 model) and it's a great place to sit. The padding is a bit thin, but I just threw a small thin pillow underneath the sitting portion and now it's fine. It's sturdy and supportive, looks great, and the power strap guarantee's it not falling apart, even for the more heavyset people.
In terms of using it for a GT4 setup, it rocks a bit when applying pressure to the pedals, so I put some PVC piping around it so it wouldn't go anywhere. I can race more comfortably now, and the cockpit looks a bit less DIY.
However, it is a bit overpriced ($80.00 USD) but I found mine off craigslist in perfect condition for about 30.00.