Two of the four times I've tried BK were crap. I've tried twice at Cavendish Square and they were good. The other two times were in Long Street and Tableview. Besides the dirty tables, floor and poor food, the Long street branch even had the gumption to try and pass off my friend's vanilla milkshake as a strawberry milkshake.
Visited the tableview branch yesterday. The shop was clean and the service was great, but the burgers were crap. We ordered the whopper and long chilli cheese burgers. Tasted gummy and rubbery (can't think of any other way to describe it) and kept sticking to the roof of my mouth. Only ate about a quarter of it and had to discard the rest. Some of the chips still had green fried skins and little black spots on them. Not stepping foot into a BK for the foreseeable future.