Hey, i've stayed along hotel plaza boulevard at DTD the past couple of years and apart from the extra buses for u during extra magic hours, the same buses serve 6 hotels (normally 7). They run an hour before opening every half hour from the hotels and are pretty good at staying on time. Usually Hilton is first or second stop- ideal in the morning as they get busy, and evening when your sleepy. They also lay on extra buses at closing time, but don't be surpised if there's a pretty long wait. We've usually found that after closing there's a whole bus load in front of us but we get on the second.
For ease of use they all pick up at space 26 in the parks- there's not always shelter by the stop so if it's rainy get a poncho/umbrella or get wet. The only slightly annoying one is AK where pick up from the park changes to every hour in the middle of the day. It just means you have to plan better (we took the car there).
I've heard many people complaining about the service, but after using disney's own service to get around to boardwalk and epcot from DTD i think we're pretty lucky.