One big thing for us is that we can leave the wheelchair/strollers in the car along with the park bags that don't need to be repacked. There is no dragging a stroller on and off buses. We choose resorts that allow you to park just outside your room which means no walk to the bus stop. You get to choose a direct route to your destination. You can pick up supplies at the grocery store or hit the outlet store with ease. If you book through
AAA you get the Diamond card which allows you to park in preferred parking which is near the handicapped parking in most cases. No need for a tram. MK kindgom is the only park that it doesn't make sense to drive to as you must park at the TTC and use Disney Transportation from there. It took us 1 hour 15 minutes to catch a bus and ride it from DTD to the Contemporary. By car the trip is maybe 10 minutes. When I'm on vacation I can't stand wasting time. Since you walk to your car there is no waiting to be on your way and you get directly to your destination. We used to ONLY use WDW transportation and thought it was wonderful until that first time we rented a car. What a difference. Chris and I thought that since the ME is offered and it was just the 2 of us that the buses would be fine. I bet we spend a good 5 hours if not more on Disney buses/monorails on our 4 day trip. That is 5 hours that we could have done something else, like sleep

Obviously we would have spent some time in the car, but it would have easily been reduced by 1/2.