I signed up with Copeac and have not used them at all, I have to put some time aside to really take a look at their offers. Ive played with Azoogle a bit, but the company i use most often for CPA offers is CJ.
I have accounts with all 3. Although the only 1 I have really used is CPA Empire. They seem to be a decent company, they wire money on time but, one drawback seems they go through AM's quite a bit. But also, weekly wires, you only have to be at 1K. So I guess you take the good with the bad.