I have a sister that is severely Autistic and is 48-years old. Whenever my parents and sister visit us we always take a trip to WDW, its a place where my sister Mary can have fun and about the only place to make her smile.
We utilized the "special card" every time we went with Mary. It made it easier and more enjoyable to get her on favorite rides without the stress of waiting which she cannot ever ever do! Mary was always in a wheelchair, it was easier to keep her in a controlled situation and the Special assistance pass would bring us to exits to get on rides and attractions. We never overused this special card, in fact when we would go to WDW with my Parents and sister we went on significantly fewer rides, spend most of the time walking around, relaxing, watching entertainment, and keeping Mary happy and quiet.
When the program changed after the big to-do about miss use of the special assistance card we were finally able to go back with them this last Christmas. So it was our first time trying the "new" system. I can report it worked just fine. You go up to the ride you want to go on, and they stamp a card with a time to go back... similar to a fast pass. Then you just go back at the specified time and they let you in the fast-pass line or handicapped entrance depending on the attraction. It was never a long wait, and was never inconvenient.
I guess I just wanted everyone to hear my family's story. Here is a picture of my beautiful Mom and sister Mary! And the second picture is from left to right: my hubby, me, my son, my handsome and awesome dad, my momma, and Mary in the wheelchair.