We booked the Carnival Dream as a preface to our upcoming (6/12/11) Med cruise aboard the brand new Carnival Magic. We achieved Platinum status on Fantasy class boats (we even sailed the Holiday once).
Port Canaveral is a well-oiled machine. We were on and off in no time with no hassle. The ship was bragging that they got 2,000 people off the boat in 20 minutes as we were boarding.
We booked the Spa deck (deck 12) on the recommendation of our Carnival agent. It was such a pleasant experience we tried to change our Magic Vista deck cabin to the Spa deck. We both exercise regularly on board, so having the gym and spa a short stroll down the gangway was very convenient. Spa deck cabins get access to the steam rooms and the mineral hot tub (it's $150 or so if you pay separately).
Comfortable and roomy. All the cabins on the Spa deck are decorated a step up from the regular deck cabins. The hallway was private and had an outside entrance to the Serenity Deck ladder. It was very quiet at all times. Plenty of storage. New style heads are roomier and easier to use than the Fantasy class heads.