Best CPA Programs (Cost Per Action)?

[build-a-host]

Lately I've been hearing a lot about using CPA (Cost Per Action) programs in place of PPC (Pay Per Click). I did a google search for "CPA Networks", and there are hundreds of them listed. My question is, do any of you guys use a CPA program? If so, which ones have you found to be the most useful and trustworthy?

Thanks in advance!

 

[Anshumanm]

Neverblue ads is the best in my opinion.