Which do you prefer ? PPC or CPA ? From which you earn more ?
I think CPA is better in long run. I know AdSense is great and it's the only reason which put PPC on top of CPA but if you loose the AdSense account there aren't many alternative PPC networks you can use. At least none can compare with AdSense. CPA always have lot of good networks and programs so if you loose one you can use another without a problem. Also unlike AdSense are not gonna get your account banned from CPA networks.