Any experience with adbrite/etology/adengage?

Hey all
Do any of you people have any experience with the companies I mentioned(adbrite/etology/adengage) in an advertisers perspective?’
Because i’m considering to buy some advertising using one of these companies, but I don’t want to do this if it’s crap.
I would not be buying network ads, but ads on a certain site.
If it would help you, MY site is an entertainment and video site .

Original post by Chrilz