In terms of raw traffic from the AVS links list, Adult Check is still #1.
However, with their new tiering system for the links list you need to be promoting an adult check gold site with your regular sites in order to really cash in on that traffic.
If you're building a premium site and then building feeders to upsell, adult check is going to give you the most traffic to your feeders and the best recurring numbers on your premium renewals.
If you want to get sites on the links list that promote basically anything else, Sex Key is your best bet. (Speaking in terms of raw traffic from the system)
Cyberage would be next on the list, and after that its 6:5 and pick em.
Its been my experience that it doesn't really matter which AVS you're using to promote your site. If your tour sells, it sells. If they want what you've got behind the AVS script bad enough, they'll pony up the dough. (Or at least the CC number in the case of a "free" AVS)
Your mileage may vary.
My
