We rode it between Ft. Lauderdale and West Palm Beach 2 months ago. The train and stations are very nice, and the employees fall all over themselves to be pleasant and helpful. The only minus was the 35 minute trip to WPB took over and hour due to extreme safety precautions at the many crossings. Two people crossing the tracks by foot/bike had previously been killed. The trip back was on-time.
Future plans call for a line between Miami and Orlando. Not sure about the appeal of the Orlando destination since you would need a rental car once there (unless a local bus service was tied into your train trip). Orlando is a huge place with many attractions.