hi john, me and Amanda used carole and tayfuns transfer last year, tbh I was really worried that they wouldn't show up at dalaman, but the driver did, he stopped off just past the airport and bought us some bottled water and the whole experience was good, the return journey was in a bit more posher van air con and tinted windows etc.
I think they must use local (to them) drivers with own vehicles and take a slice of the top on the asking price, yes i'd use them again for transfers and trips too.