Technically, I have seen one, and they are interesting but I havent cooked on one. The one I saw was being used at a fund raising rib cookoff, where teams had to cook quite a large amount of ribs, to sell to the public. This team also happened to be a competition team, but it was neat to be able to look inside (briefly with the lid open) to see how roomy it is, including being able to add a rack to give extra rack space if you wanted to and to see one in person. Not real helpful...I would be interested in one if I had the money.