DH & I are in our mid-30s and had previously cruised once with Carnival and Royal Caribbean. We boarded the Carnival Spirit in Vancouver, BC and took a 3-night Cruise to Nowhere aka Repositioning cruise to San Pedro, CA. We stayed no the boat and continued on for the 9-night Mexican Riviera cruise with stops in Manzanillo, Puerto Vallarta, Cabo San Lucas, and Ensenada.
Overall, it was a good cruise. We wish we would have had another day in Cabo and we learned we aren't really big on too many sea days but nothing went wrong and everything went smoothly. We like Carnival because they make things easy as far as booking, bon voyage, picking a room, general self-help customer service online, etc. It looks like we will be sailing with them again next year, possibly twice.
PROS:
Lots of storage, good location, quiet.