Just my newbie 2 cents and mainly from a surfers point of view but....
As ronnie has said, the images are poor quality which is an instant put off, bandwidth is cheap enough for you to use nice hi-rez ones. Far too much clutter if you ask me in general.
Your tour has to be a hard hitting, high impact, whack in the face of a page and the join page has to close the deal. I know it's not the same niche but compare it to something like
http://www.lady-sonia.com/
You want nice clean pages with obvious join links and the good points of the site in clear bold text. Surfer attention span is very low - you need to give it to them on a plate, at your site I feel as though I kind of have to wade through loads of text to find out that it's even a paysite.
It might be worth you getting the tour designed for you by someone who knows what you are doing because it seems like your actual content is pretty damn good. Especially when you are compared to the hundreds of paysites that are just a few pictures and movies slung in the members area. If you truly give what you claim to on the tour, you shouldn't have any problem retaining members, you just have to work on getting them through the front door in the first place.
Good luck with your site, I'd promote you if you had a good tour and 50%+ revshare.