It's an advertising site from the same folk as Escort Ireland (which seems really popular). There are fewer women than AW, and in general, if they're on ES, they'll also be on AW. However, I always feel it's the better ones that are on both - far fewer Roms for one thing. I tend to check ES before AW, to be honest.
However, it's pretty barren unless you're looking in Aberdeen, Edinburgh or Glasgow.