My experience with long-haul taxis spans many years, but only two drivers...Alfred Barrett and Kingsley James. Alfred is gone, Rest His Soul. Kingsley is quite busy these days and you may get one of his drivers, all of which are excellent, for one of the airport runs, but Kingsley is in charge of the tours and is super knowledgeable, super friendly, safe and secure.
I am sure the reviews of Linton and Michael are spot on, I have only heard good things about both.