Check the Mears site. There are other limo/taxi sites but this will give you and idea. Unless there is a big price.
We drive since we are 5 hrs door to door north of WDW. But I have rented when I arrived the day before DW from a business trip to allow flexability to stock the unit before her arrival. I personally like having my own car. We even drive to the parks many days to allow more flexability when park hopping.
-The car/van is there at your schedule, no waiting
-You can go where ever you want if you finish early and explore more of WDW or Orlando (great for resort exploring)
-No parking fees that need to be added onto the rental price. They can add up
-No need to worry about an accident driving on the other side of the road (Us crazy Yanks)
-No need to worry if the driver wants to partake in an adult beverage or two. Everyone can have fun. After all, it is a vacation