We have always used a towncar (unless renting a car, did that a few times as well) and it's very quick. We only bring a carry-on each, so head straight to the luggage pickup area, and they are there with a sign with our name on it. It is very quick, and a nice service. We do a quick stop for some snacks and drinks.
The only problem is, the one I prefer I can't mention on this board. I got their name from another well known Disney info site. I really like them a lot!
I used Tiffany once, but the driver one way kind of seemed, well, not my favorite. So while not too bad, I prefer this other one way better.
It doesn't look it's the official MCO site list. 
My DH and I agree with the towncar service. We have used Tiffany each time and have used a Towncar and van. Only once did the driver make us uncomfortable with his speed and we just requested another driver the next year. They have alwys been prompt and car/van was always clean. DH and I agree that this is very much a luxury--we work so hard during the year--our attitude is that this is pat of the vacation--an attraction, so to speak. This year my parents (who are very budget conscious) will be going with us so my DH and I will pay for this service. My mom will get a kick out of someone holding up the sign in baggage claim for us. I don't know maybe that is kinda dumb but I think it will be a nice/fun touch for them. They have always worked so hard for other people. It is like being wisked away with your own private chauffer--I am crazy.
Heehee, he screamed "UNCLE" after twisting his arm for a few minutes. 
Gotta love your parents when you are in your late 30s/40s and they are 70ish and on a budget. I did the DDP so mom and I wouldn't have to listen to the food price speech at each park. Daddy is sooooo cute.
