Do you have specific types of sites that you only use PPS (Pay Per Signup) or recurring sponsors on?

For example, on TGP galleries do you tend to go for recurring sponsors over pps or the other way around?

What about free sites? AEN / AVS sites? TGPs?

Have you found a specific form of payout model that works best for you on the various types of sites you build and, if not, why do you currently use the types of sponsors on each?

Regards,

Lee