I have never had more than a handful of website hits from Captain69, and that was only when I had a review on there but I think it's probably better for London. You could also try Cherry Girls but it's expensive (?100 per month) and the word around the campfire would suggest that it isn't as good as it used to be, but I daresay some London-based ladies might be able to add to that.
I tried CherryGirls recently-ish (maybe 5-6 months ago now?) and was very disappointed; the costs were astronomical and all I got from there were a few timewastery calls and emails. Not even a large volume of timewasters! Just one or two - and they would usually mention CherryGirls in their call, as I think that's suggested by the site. Anyway, I thought the costs were mental considering how useless the ad was, but perhaps because my rates are too 'cheap' to go into their High Class section (and I wasn't adding another ?200 to the overall costs to get into the "Brunette" section or "Student" section) maybe that's why I didn't get much attention?
Also, I must note that when I went into the office to meet the site owner and his 'team' (there are at least two guys and one lady, who I never did meet, working for CherryGirls) so they could 'verify' me, he really did try to push me to sign up for some kind of "special site membership" where I'd be heavily promoted to some "special clients" (who would be any bloody person who paid a subscription fee to CG, in fact) to whom I'd be expected to offer some "special discounts". So basically, this brilliant idea would leave me earning less money while meeting a bunch of entitled gits, while CherryGirls earned a lovely fee for arranging this wonderful plan. I obviously nodded along, praised both blokes for their business acumen, and got the hell out of there ASAP never to speak to them again (especially as I wasn't going to be paying for another month on their site,
especially as they put my website link in wrong on the ad they made for me and didn't rectify it for ages). But I'm sure other people have had differing experiences with them; that's just my personal one.
I must emphasise here the complete randomness of the industry in terms of advertising success - like someone else said in another thread, you could have two identical twin escorts in the same town doing the same advertising, and one would probably get a completely different response from the ads than the other. You can never fully predict what'll happen after you pay your ?2, ?30 or ?100+, so to be honest, the best thing to do is check out other escorts' sites (they'll often have banner ads returning links with the sites they're listed on) to find out what's popular, and do some careful experimenting yourself.
Most of my business comes directly from my site, and I always make sure it, my pictures and my blog are up to date and regularly refreshed - this is really important (and also applies to ads like AW; there's no point just throwing money at something and expecting the to roll in if your ads look tired and your last blog entry was in January.
Just wanted to second this! Keep your site/blog/pics really up-to-date.