I only ever use WDW transportation. Not Having to Drive is for me one of the big selling points of a WDW vacation. I don't like the idea of driving an unfamiliar car around an unfamiliar place. (Trust me, I don't care how good the signage is, I would get lost and frustrated.)
I've had generally good luck with the buses, and really don't mind if I have to wait for one, or go from POFQ all through POR, etc. It's vacation, and as a PP said, having to wait/sit on a bus or boat can be a nice enforced break (I'm pretty commando, too).