I buy traffic from plugrush, pretty much testing all their sources and delivery options, Im not buying huge amounts but its like 30 - 60 k per day, depending on what type of traffic I buy on agiven day ...
There is a significant amount of fake traffic in the mix, but still, they are one of the best sources to use considering the price per K I can achieve. Sure, you gotta block a shitload of sites and constantly monitor it, but there are good sources in the mix.
There are WAY worse brokers out there and I still have to figure out how they can survive for so long, plugrush is still decent
Maybe one day Im drunk enough to share the results of my tracking tests, you would wonder what kind of crap some brokers sell for years
If all were like plugrush, this would be a better world