You must be talking about the Mears shuttle. Some people have had good luck using them. Many others (like me) will never use them again. Unlike a car service that is waiting to take you directly to your hotel Mears takes a lot of people to a lot of different hotels. You may also have to wait at the airport for another flight to come in so they can load up their vehicles. Mears is cost efficient for one or two people. Over that a car service is your better deal. If comfort and convenience are important to you do not use Mears.
There are many fine car services that you can read about on these boards.