Signed up last fall but then never saw my ads. Tried it again late last week and added more keywords. They were approved within minutes, as was a new campaign, and I am now receiving well-converting traffic for half the price of AdWords. So far, so good!
I am getting plenty of clicks but no conversions except one... since Friday when we launched. These are the same tried and true campaigns that are extremely successful on other venues. It is making me wonder...
I'm getting conversions and making a profit so far with AdCenter. I'm having a problem separating out orders to know exactly what my conversion rate is, so I'm not sure how it compares to AdWords, but it's close. My cost per click, though, is well under what I have to spend on AdWords.
[added] The number of impressions and clicks, though, is well below AdWords.