Cuil is new and it wouldn't surprise me if they penalize adsense users, so it is hard to tell. I would if I were them at least at first. Google on the other hand seems to penalize sites it has ripped adsense off of. They totally wreaked havoc with a local blog. First they said too many clicks from the same spots the site had 10k a day M-F impressions, 90% of which were from 20 stations at the local welfare/job center. When we switched it to bidvertiser, adbrite and scribefire networks then dropped PR from 6 to 0 and took it from page 1 top slot to page 700.

I am waiting to see how this site plays out with cuil. I wonder how long it will be before they have their own adnetwork?