It does look slippery but it's actually not.
The only issue I have with it are the bits on the side on the bottom and back, as if you have a large build regardless of whether it's muscle, fat or you are just generally have a big body then the chair might not be a good investment, as they start at £150.
It will take some getting use to, but it is still so much comfier than my old chair so it's worth it for me.
It is the standard GT Omega Racing Pro not the XL version, but looking at the measurements on the site the bottom part which you sit on, is smaller on the XL version than the none XL version.
Either way it's pushing me to loose some weight so it's a good thing