We've used Mears several times to get to Universal.
It was $12 pp (there are only 2 of us...if there were more, I would use a towncar).
You call the day before and set up your time. They pick up every hour. Depending on how many have reserved, a van or full-size bus comes. It does stop at other resorts (again depending on how many people are scheduled).
You call ahead to get picked up from Universal also.