We used the HIFS shuttle service in Feb 2002. It does NOT run on a regular basis. Parks and scheduled times differ daily.
However, we made it work for us. My husband picked up the schedule from the desk and we sat down and determined when we would go where. It worked out fine.
In fact, the bus was only crowded one night and that was Saturday at the close of Magic Kingdom. We all had a seat and no one was left standing.
Overall my family did not have any issue with the bus service. We utilized the HIFS shuttle everytime we went to a park except day one. We came into Orlando and unloaded our luggage and took off to the parks

in a cab. We wanted to go right then.
We are heading back to HIFS in March this year and are not planning on renting a car. We will be using the bus service again. I have budgeted in $100 for cab fare if necessary. I don't think it will be needed, but you never know.
I did look into car rental, but we would need a minivan and the cost would be near $250 for the week. I would rather use the bus service and the occassional cab, spending the $150 on more treats for the kids and grandma & grandpa.
have a nice time at the HIFS and search over the bus schedule on Day1 to help plan your itinerary. If you do that, I think you'll find the shuttle service adequate.
