jcemom, if you're staying at the Hyatt, then I'd definitely do the
DCL busses since that entitles you to leave your luggage in the hall outside your room at the Hyatt and have it MAGICALLY apprear in your stateroom on the ship later in the day. If you do a towncar, I don't know if the driver can come in the hotel to get your luggage so you'd probably have to get the bell hops to transport your luggage to the curb.
Since I go for totaly comfort and the least possible effort, my vote is for the DCL transfers with the bus.