The Superferry was awesome. No need to rent a car plus gas price cheaper than other islands.  Renting a car means catching a shuttle to the rent a car place.  No baggage fees. No need someone to take you to the airport and pick you up.  Can stretch your legs and lounge at the snack bar.  No need to bundle up the golf bags.  
The bad is the schedule.  No choice but leave early morning and return late afternoon.  The ride could be bumpy going but smooth returning home.  Wish we still had them.