The "break even" point between
DCL transfers and private limo transfers is generally at 3 people. More than 3, it is cheaper to go private. In addition, the private limo services will run on YOUR time schedule.
The way they usually work is that they are booked ahead. The driver meets you at the baggage check area of MCO and takes your bags to the waiting vehicle. The type of vehicle depends on the number of people involved. Vans and limos are generally equipped with a DVD player to keep little people occupied. It takes about 45-50 minutes to the port. The driver takes you to the luggage drop off area where your bags are handed off to the ship porters. You DO need to place your cruise tags on the luggage between the time you collect them at baggage check and the time you give them to the porters.
I'm familiar with Tiffany Limo, Happy Limo, and FL limo. The prices are fairly close. The price does include a tip to the driver, although many people tip additionally.
You can book a limo one way or round trip...as above, another alternative is a rental vehicle which is dropped off near the port.