I have been using it for a month or so as an advertiser not as an ad host. I find that a lot of people are getting carried away and paying way more than they should for adverising that is completely unrelated to the site they buy an ad on. This drives the prices up too high and then I dont advertise again and I wont until the prices are realistic. I see a big potential for falsely high bids because you can bid until you know exactly what the high bidders max is then you can sit at a price 10cents below them and make them pay the maximum price. You as an advertiser could create your own bidding account and drive your own prices up. So I do see a flaw that causes me concern. I have a rather large advertising budget for my site but I wont use them until I am sure I am not getting scammed by the backup bidders.