To me, whether a person should drive or use Disney Transport comes down to that person's temperment and personal opinions.
I have always used Disney Transport and never want to drive at WDW. WHY? Well, for me, A Disney vacation is just about my only chance to live for a week without driving. I drive everywhere every day in real life, and I LOVE the idea of not having to drive for a week. Just the idea of not needing to carry around a car key is truly liberating to me; it may sound crazy, but it's true. I really resent my brother-in-law moving out of Manhattan, because weekends at his place were the same way -- I didn't see my car for 2 days or so.
Disney World is about the only place I can go where I don't feel hampered by not driving. Almost every place else I've ever gone I've either rented a car or wished I did.
To be fair, I must admit that I have no interest in going to table service restaurants in other resorts. With the kids, we're happy to do counter service and a character meal or two all week. I suspect that if I was the type to want to go to other resorts often, I'd probably feel frustrated at the transfers and time necessary to get around resort-to-resort. But I think good planning can make that problem go away, too. I think if I was staying at CBR but wanted dinner at Boma I would plan to tour AK that day and then go straight from AK to AKL, and then after dinner plan to do the EMH at whatever park might be having EMH that night (we'd make sure to plan it for a day when SOME park had EMH), and then take the normal bus back to CBR from that park.
I may be in the minority, but like I said, I LOVE not driving for a week.
Maybe it's also that I'm very accustommed to buses. I grew up in Philadelphia, where starting in 7th grade we had to take regular city public transportation buses (not school buses) to school, and I didn't own a car until my 2nd semester of senior year of college -- I used Greyhound and public transit to get between college and home for visits.