Background - We have been on all the major cruise lines and have mostly been on Celebrity and Royal Caribbean. Have been on three previous European cruises (2 Celebrity, 1 RCCL).
Flights - Booked flights independently and had two direct flights that worked out great.
Pre-cruise - we booked a Carnival pre-cruise hotel - Fira Palace. We paid a little more booking through Carnival, but we didn't want any hassle at the start of the trip. Transfers worked fine. Hotel was very nice although not centrally located to many of the main sites,but we just spent one night since we had been in Barcelona before. Took the Carnival transfer to the ship around 10:15 without any issues.
Embarkation - We have never been on a ship quicker. Carnival certainly planned it perfectly to get us onto the ship before the crowds arrived. We were at the pool having a drink within 20 minutes of getting off the bus.
Ship - ship is truly beautiful. Public spaces are as nice as any ship I have been on. Certainly a great upgrade for Carnival over the neon Farcus designs. Nice to have a ship with outdoor lounge seating areas on the promenade deck. One of the few ships that you could walk completely around the promenade deck outside. Public spaces were all very nice with standouts being the Red Frog pub and Ocean plaza.
One design flaw was only having two pools for this size ship. Main pool had the movie screen blaring with some type of entertainment and the back pool area is relatively small. They did have additional loungers on the promenade deck with a shower or whirlpool for water relief only.
Cabin - we had an outside balcony cabin just under the pool deck. Room had plenty of storage. Bathroom was larger than usual. Flat screen TV that swiveled out to view from bed and a balcony with two chairs and table. Room steward was very nice, but more impersonal service than other Carnival ships certainly due to the size of ship and number of rooms that they needed to service. The ship seemed to run out of pool towels very often for a new ship and we had to ask multiple days for a new set in the cabin to take to the pool.
Food - We ate in the main dining room (your-time dining), Italian restaurant, steakhouse and the cafe for dinner. Food choices and quality in the main dining room were much better than our last few cruises on Celebrity. Service was always very efficient and we never waited a minute to be seated showing up between 7:15-7:30. The cafeteria had many of the same choices that were being served in the dining room that night so there was always variety. Italian restaurant was well worth the $12 charge per person. The steakhouse is expensive at $35 pp, but the meal was fantastic except for the disappointing (not in size, but quality) cheesecake. Guy's burger joint was good for a quick meal, but closed at 6pm each day. The pizza was custom made, but very slow at peak times when they should just pre-make pies since you know they will go quickly. Service was uniformly good in all eating areas.
Entertainment - The main shows were shorter (40 minutes) and not on par with other Carnival ships or other cruise lines. You were usually tired at night so it wasn't a big deal. The Divas show was especially bad with Divos needing to sing Divas songs since there were only a few female singers. Never had any interest in seeing any of the Hasbro shows. They had about 6 different acts working through the lounges at night. Most were very good, but a couple were very similar country singing guitar players who were a bit repetitive. Didn't really notice the activities since you were off the ship most days. Cruise Director - John was very amusing and the highlight of any of the main showroom shows. Announcement were always minimal except for John plugging the spa on a daily basis.
Fellow passengers - about 70% of the ship was American. Found that on average people were not as friendly as you seen on other cruises for some reason. People were friendly on tours, but there didn't seem to be the usual daily interaction I have seen on most cruises. Certainly some culture shock with some of the Eastern European guests who were quite rude and many people seemed to have issues at some point with them.
Complaints - The biggest issue is that Carnival didn't provide daily information in your cabin regarding port information that we have received on the other cruise lines in Europe. You were always given basic transportation info/customs info/site info on the other cruise lines. John did two shows that were rebroadcast on TV that gave you some of this critical information. If you didn't see this and you didn't do your own homework on the port, you were screwed. The time they provide guest info in Venice it was actually a disaster. There were signs posted to follow to the Carnival Breeze that easily took you at least a few miles out of the way in the 95 degree heat. You need to do your own homework on the ports which I know many people will do on this type of trip. Carnival seemed to take the attitude that if you didn't take one of their excursions, that you were on your own and this was a shame since they did so many things well on this cruise. They always made a big deal about who was late to get back on the ship, but this may have been a moot point if they told people how to get back to the ship properly.
Ports - I am sure that people have seen many written about these ports so I won't go into detail. This was a great cruise since we had overnights in both Rome and Venice. We booked hotels in both cities and were able to have the great combination of staying in port and having a great ship to go back to.
Overall - a thoroughly enjoyable cruise experience despite the mid 90's temperatures and high humidity.