Walt Disney World is a big place. Should you rent a car or take the bus? These are many things to think about. Are you going to drive to the parks or go anyplace off Disney grounds? Are you just going to spend your time in Walt Disney World? If you decide to rent a car when you are at the airport there is the stress of driving to Disney. Walt Disney World is about 30 miles away from the airport. The road that you have to take is a Toll Road. So you have to have change for that. The parking at the resort will give to a parking pass. Then when you drive to the parks there is the stress of finding a space. Since you have the parking pass the parking is free. If you decide on going someplace away from Disney. Having a rental would be good. But what if you are just going to spend the whole time at Disney a car might not be a good thing.
Disney has their own bus system. There are buses that go to the parks and to all the resort. All the driving will be up to someone else. So you can enjoy your vacation. Depending on what resort you pick the farthest park is up to a 20 minute run. If you decide to leave the parks after closing the bus can get full fast so you might have to wait for another bus. Disney is fast at getting buses to the parks to get you back to your resort.
Buses run until one hour after the last park closing. If you want to go to another resort the bus will take you there but when getting back to your resort you have to go to a park or to Downtown Disney to catch your other bus.
So you have to decide which way would be good for you. When I go to Walt Disney World I always take the bus. They are very good but when leaving the park after closing you could be waiting for a while. The drivers are friendly. They will answer your questions.