I am testing various brokers now too, so far plugrush seems to work best for popunders, juicyads was good some time ago, then they went really down for me. Today Im doing a small popunder test with exoclick, so I will know shortly.
As for banners, I did pretty well with exoclick, now they seem to work not so good anymore, I am testing adxpansion today to be able to compare. I wil also try ero-advertising for banners soon.
Generally speaking, the performance of broker banners is really poor IMO, what I see is a CTR of about 0.4-0.5% and only about 1.5 cents per click, which is about 7 cents per 1000 banner impressions ... these are numbers from exoclick for example, for a typical mix of traffic with US being the most etc...
I am really curious about the brokers I will test, hopefull someone pays more than that
