I have checked out a bunch of them. So, I created a website:
www.PPCIncome.com which reviews DomainSponsor, Fabulous, Sedo, DomainSpa, TrafficZ & NetVisibility.
Google feeds advertisers to DomainSponsor and Sedo, I believe.
Without a doubt, DomainSponsor has worked best for my diversified domain portfolio. I am talking about bottom line. Now, you need to have about 1000 unique views per day to qualify for DS Premier, which is the way you get the Google links and the much higher CPM. I have been averaging around $18/cpm with DS Premier.
The stats on Fabulous are absolutely the best, with DS in 2nd place.
Sedo is good for some foreign traffic, especially UK.