I've been on six Carnival cruises and have two more booked, one leaving in two weeks.
There are seven (actually eight) classes of Carnival ships:
Fantasy class - Fantasy, Ecstasy, Sensation, Fascination, Imagination, Inspiration, Elation & Paradise
Spirit class - Spirit, Pride, Legend & Miracle
Destiny class - Destiny, Triumph & Victory (actually the Destiny is a little different than the Triumph & Victory, thus the eighth class)
Conquest class - Conquest, Glory, Valor, Liberty & Freedom
Splendor class - the Splendor is the only ship in this class
Dream class - Dream, Magic & Breeze (the Magic is almost complete and the Breeze will not be finished for about one year).
I have not been on the Splendor or Dream.
The Fantasy class is made up of the oldest and smallest ships in the fleet. These ships are used for the three, four and five night cruises. There are no balcony cabins (the suites have balconies, but there are no category eight cabins). The lifeboats block the view from the Verandah deck. All of these ships except the Elation and Paradise have been upgraded with an improved pool area, an adult only Serenity deck and a water works. Actually the Elation and the Paradise have the adult only Serenity deck, but not the improved pool area and the water works (a miniature water park). However, it will be added to each ship in the near future. These ships do not have the optional extra cost steakhouse restaurant nor the Seaside Theater (a very large outdoor TV screen for showing movies and sports).
The Spirit class is my favorite class of ship because it is easy to navigate (because it does not have a mid ship dining room - both dining rooms are in the back of the ship and is in fact one large two level dining room), it is just the right size (not too big, not too small) and these ships have the biggest passenger ratio of all Carnival ship (meaning the most space per passenger). These are currently the largest Carnival ships that can fit through the Panama Canal. These ships have the optional extra cost steakhouse but not the Seaside Theater nor the water works. These ships also have one pool with a sliding roof (open in good weather, closed when the weather is not so good).
The Destiny class is more or less a 90% scale version of the Conquest class, except the that they do not have the optional extra cost steakhouse.
The Conquest class is about 10% larger than the Destiny class and includes the Seaside Theater, a pool with a sliding roof and the optional extra cost steakhouse. It does not have the water works. All Carnival ships (all 24 ships) have water slides, multiple pools, a casino, a main show lounge, smaller lounges, a dance club, game room (arcade) and several bars.
The Splendor is just a little bit bigger than the Conquest class (its sister ships are actually in the Costa fleet - Costa is an Italian line owned by Carnival). It has the optional steakhouse, water works and a pool with a sliding roof. I do not believe it has the Seaside Theater.
The Dream class is Carnival biggest and newest class of ships. These ships have it all, the steakhouse, the water works, Serenity deck, a pool with a sliding roof and the Seaside theater.
The Fantasy class is made up of the oldest and smallest ships in the fleet. These ships are used for the three, four and five night cruises. There are no balcony cabins (the suites have balconies, but there are no category eight cabins).
We were on Carnival Elation six months ago. As Cruizer mentioned, it is one of the ships that didn't have the new pool and splash areas. Yet, we found it nice, anyway. At a couple of ports, we docked next to ships that had received these upgrades, so I got a good look. The waterworks area replaced a small pool and the basketball court. And, the midships pool on Carnival Elation was just fine. I guess what I'm saying is that you can't go wrong with either (unless you are an avid basketball player).
And, good to see you, Jeff and Susana! Yes, as they stated, some of the Fantasy-class ships have received (or will receive) refurbishments that will add balconies onto some existing oceanview cabins.
Not much help here however we were on the Freedom last May and have booked another cruise on it this October.
It has a similar feel to it as the 'Caribbean Princess' class of ships, excepts you have better balconies which are partially covered.
We sailed on the Oceanic also, and Carnival's Festivale. That was back when ships looked like ships, not huge floating hotels. NCl's new Epic is one of the worst I have seen in that regard.
Cruising still beats everything else though.
We've been on 16 Carnival cruises and 16 different ships. We've had one cruise we weren't really happy with, but that was due to staff problems and they were probably corrected when the ship was repositioned.
My preference is the Spirit Class ships: Spirit, Pride, Legend, Miracle. They seem to be easier to navigate and although they are big they don't seem quite as big somehow. The layout of the Lido deck is also better on these ship.
On the other hand, the Conquest Class ships (Conquest, Glory, Valor, Liberty, Freedom) have a few extras that the others don't, like a special place for Fish & Chips (which also includes other fried seafood). My husband plans on eating there often, we may have to split up since I like to eat lunch in the dining room!
I have no problem with the Fantasy Class ships (Fantasy, Ecstasy, Fascination, Imagination, Inspiration, Elation, and Paradise) either. (Or any of the other classes I haven't mentioned.)
The decor is more to my taste on some ships than on others. We've found the decor to be one of the "fun" things to see once we board. Carnival, to this point, even includes floors and ceiling when they decorate. There was one ship where I remember sitting and waiting for our number to be called for debarkation, looking up I saw something in the decor I hadn't noticed during the week we were onboard. It was in a place we had gone by or been near often, too.
On some ships you can't go from one end of the ship to the other on the same deck, but they hand out - or have setting around - maps that help you navigate the ship and before you know it you don't need the map anymore. (There are also maps on the wall at the elevators.)
So far we've chosen our cruises based on the ports we want to go to and then look to see what ships we haven't been on yet. We are really excited this year as we have a new port or two AND a new ship!
If you're an addicted cruiser, there is no such thing as a bad ship. Each individual cruise is unique. We have done a B2B, 7 day eastern Caribbean, backed up with a 7 day western Caribbean. You could easily have been on different ships, the personality of the passengers changed that much. Not better or worse, just different.
If there is a major problem on a cruise, that might be a bad cruise. We have 51 cruises, none bad. The worst I ever had was terrific. 15 Carnival cruises on every class of ship they have/had. And will continue to book Carnival whenever they have the itinerary we want. We now consider a 7 day cruise a short cruise. We would still cruise a Fantasy class ship if they ran an itinerary we wanted that was 7 days, OR MORE. We also like the Spirit class, but its the CRUISE, not the ship for us.