I personally started out with AzoogleAds (Epic Advertising) and it's still my largest network. The offers are really good, especially the exclusive ones.
I'm also with NeverBlue and Hydra and both are good, although I miss the conversion pixel tracking on Hydra, but they are working on it. This is one very important tool and both AzoogleAds and NeverBlue offer Conversion Pixel Tracking so in PPC campaigns you can see which keywords converted into leads.
Which Networks are you using and where do you have to most success?
