I can confirm that it is possible, even for an average at best 30 year old guy like me, to meet women on Fab. I've met five. Go in, be polite, don't go too heavy on the sex talk etc. and you can be successful.
However - as far as I'm concerned, punting is way better. For around £100 you can get a guaranteed shag with a gorgeous woman, get dressed, leave and get on with your life. With Fab, it's never quite that simple. Firstly, hardly any of the women are gorgeous. Secondly, feelings and other complications get involved, even if women swear blind they're just in it for the fun, they're not - usually they are kind of 'broken' women, divorced, lonely, otherwise unsatisfied looking for a thrill and it all gets complicated.
I firmly, firmly believe that punting beats all these supposedly great alternatives like swinging, being a sugar daddy etc. And that goes x 100 if you're in a relationship.