My parents always drive and leave the car in the resort lot for the duration and take Disney transportation to the parks. It's just easier and lets you enjoy the magic as opposed to trying to navigate yourself. Except that one time that after waiting 45 minutes at Poly for the AK bus they just drove themselves.
And this is why I prefer to drive myself most of the time.
Disney transportation is great and all, but it's very easy to navigate around WDW by car and in almost all cases I've gotten to my destination more quickly via personal car than busses once you add waiting times, etc.
I know, I know, someone is going to yell, "I'm on vacation! I don't want to drive!" which is a perfectly valid point. So driving yourself around Disney isn't for everyone. I like driving and enjoy being able to control my stay, so it really works for me.
For example, let's say you are staying at CBR. You want to go to dinner at the Boardwalk. You stand and wait for a bus at CBR, you ride the bus to Epcot, you stand at Epcot and wait for the bus to Boardwalk (or you walk). To get back it's the reverse - you are talking at least an hour of travel time, when in fact you could get yourself there in about 10 minutes by car.
I find the same to the theme parks, with the possible exception of the MK. It depends on how busy the MK is, and of course you also have to take the transport across the water. However, for Epcot, MGM, and AK, unless you walk out and the bus is waiting there for you, I find it much easier to just drive myself - especially so I have my vehicle should I want to get somewhere else more quickly after, on-property or not.
It's not for everyone, but I find it a lot nicer - and since I play Disney music in my car it's "Disney" enough for me.
