Spot a likely looking girl on AW, then check her out on here. I took a risk on one girl who only had the briefest of mentions on here, and that came up trumps, but not sure I'd risk it again, without a solid review.
I've used One2One once, because they have three flats local to me, but it's been the same girls in the same place every week for a while now, so I haven't bothered.