as far as always having a ton of girls on I would say...
Streamate
Cams
AWEmpire
Webcams and a few others out there as well, but everyone will have their own preference as to what converts the best for them, I did good with Cams and I'm about to try Streamate as well although their white label isn't in the affiliate account by default you have to contact them for one. (not sure what the requirements are for approval)