One thing to be careful of with ceramic cookers is their ability to absorb off flavors and everytime you cook on them the flavors come out into your food. For this reason I would be very cautious buying a used one. The previous owner may have ruined the ceramic on the inside with lighter fluid or some nasty charcoal or something. I would fire up the cooker with that royal oak you have, and smell the exhaust, if it smells bad, probably something cooked into the ceramic.
Maybe you used too much smoking wood?
XL Big Green Egg, Weber Performer Platinum, WSM 22.5"