I get slightly more hits from Punterlink than the Punternet directory on the face of it, but once you add in the ones that come from the FRs and the business I get from tours ads on there it's streets ahead of the others. I don't find it works better in London particularly either - I get virtually nothing from Adultwork when I'm at home so I can only assume that most of my bookings come from elsewhere. I get more hits from Google than anything else.
I think it's worth remembering that website hits don't necessarily equal business - I get loads from here, for example and I doubt that many of them are punters. To be honest, unless a punter actually says where he saw my ad/website, I don't ask any more - they never remember further than 'on the internet' anyway.