We mostly use a rental car. We didn't have one on our very first trip in 1991.
Every trip since has included a rental car!
We don't mind taking the boat from VWL to MK or Contemporary, or the monorail from Epcot to MK, but drive everywhere else. On our spring break trip (with 6 kids),we split up. DH and DS took the car to surf lessons while I took the girls to Chef Mickeys. Caught the bus from our resort BWV. Waited 20 minutes for the bus, stopped at Swolphin, spent 15 minutes for wheelchairs and strollers to load (issues about the lift). Stopped at BCV, waited for strollers, approx. 10 minutes, stood the rest of the way (gave up our seats to parents with little ones), 10 minutes to monorail. Waited 10 minutes for monorail, got to Contemporary 10 minutes late for our reservation that we had allowed an hour to get there.
Not my favorite form of transportation.
Deb