LuvBuzz,
We did not use the HIFS shuttle during our stay (rented a car). I can answer one of your questions, though. The shuttle is not an extra charge, it is free. I cannot compare it with Disney transportation (never used that either), however I did research the subject thoroughly before our trip and remember it being said that it is a direct run. The shuttle does not make any other stops. The ride to the parks is between 10-20 minutes. If you do a search like "HIFS, transportation (or shuttle)" I'm sure you'll find all of your questions answered. Have a great time!