The ME from the airport is super-convenient - anything to not have to handle your baggage. I am always a bit paranoid about losing bags (two places to loose them, your airline and then ME), so we tend to pack more carry-ons for these trips.
I LOVE NOT having a car. Why anyone would want a car on-site is beyond me, unless you spend a lot of time visiting the various resorts. In our experience: 80 % of the time, the wait time for buses is very short (< 10 minutes). Every once in a while, (seems like once per trip) you get stuck waiting for a bus for 30 minutes - but overall, it is nice. To me, being tied to car would be much worse than not having one. If I drove to Epcot, and then wanted to hop over to The studios, I just take a boat. With a car, I have to take a tram out to the parking lot, drive around to DHS, find a parking spot, wait for the tram to the front gate. Plus, 8 entire days without having to drive anywhere! Sign me up. The only negative again is if you want to go from one resort to another...we typically only do this once or twice a trip, and therefore we simply take a cab - it's still a huge savings over renting a car for a week.
SkierPete