We always rent a car also. It can be a pain and frustrating looking for a good rate, but for us, the convenience of being able to go where we want, when we want is priceless. Its advised to accomodate 90 minutes for some commutes between hotels (say, like is you were staying at Pop but going to Chef Mickeys at the contemporary) and that is just unacceptable for us, considering its just a few miles!
We've had to park and use the tram at parking lots, but we didn't find it to be inconvenient at all. We've never had to wait a long time.
We're also people who like to go offsite, whether its to run to get essentials for the room, to eat somewhere else, or to go shopping. Our flights are usually morning flights, so we like the ability to get to the airport on our terms --although we do enjoy checking in and using RAC at the resorts!
See you there! We're there 9/27-10/7.