This was mine and my wife's first cruise. We're in our early 30's and wanted a "happening" line instead of a geriatrics boat like Holland America. The smoke-free environment made us immediate buyers.
Our overall impression? 3.5 ribbons out of 6 (One ribbon going just to the fact that it's a smoke free ship).
The ship: even though it was built only 6 years ago it looks like something that was designed in the mid 70's. Simply put the decor is VERY TACKY and it resembles more a Vegas casino. Although the ship is clean, we couldn't find a garbage bin anywhere to throw away napkins, paper, etc...
The open-air decks: (nice feature) a lot of lounge chairs all over; (awful feature) not enough pools and the ones they have are FULL of kids.
Our cabin: I've seen motel rooms with better decor... One thing that was good was the bed (VERY COMFY).
The crew: I noticed that most crew walked around with a pout. We were situated at the very front of the ship not far from a storage room and it wasn't uncommon to see crew on break lounging around on the corridor floor. The restaurant and cabin crew were nice although the cabin steward was a little too chatty...
The shows: again, we found them on the tacky side. The stand-up shows were funny but the variety shows too much glitter and cheap costumes. Finding seats was an adventure.
The excursions: we had heard that it was cheaper to book the excursions in the port rather than on the ship. Problem is that the availability of port excursions varies tremendously as does the quality. We experienced very good service in this department although if you're in the USVI and absolutely want to go snorkeling to Buck Island beware that there are 2 Buck Islands: the first is just off St. Thomas (and it's a waste of time), the other is the world renowned snorkeling haven just off St. Croix. Make sure you are not taken in like we were.
Bottom line: we had heard that the best way to start on a cruise line is to go with Carnival because everything else after that gets better. So if you're new to the cruise scene Carnival is just for you. Next time we'll work our way up to Royal Caribbean and eventually Holland America.