First of all, after spending time reading reviews about cruises, people either love it or hate it. It is a bit scary, nobody wants a crappy vacation. This was my second cruise, the first being on Holland America to Alaska. I know HAL is generally a bit more higher-end, and for this last-minute-lower budget cruise I picked Carnival's Fantasy.
I was very impressed with how quickly we boarded the ship, is was very smooth and efficient. The rooms are not bad at all. Lets face it, this is a cruise ship, not 5 Star hotel. The room reflects the price, besides if you want to spend a lot of time in your room, then you are planning the wrong vacation! The food: Dinners was awesome!!! There was only 1 dinner that was just "OK" and I think it was just pick as everyone else's selections looked better than mine. Breakfast and lunch we ate on the Lido deck and did lack something, it was the same basic stuff everyday, it was good and there was lots of it, it was just the same everyday. Service: Overall excellent. I only had 1 cocktail server who was VERY slow, otherwise had excellent service, especially in the Celebration dining room. I did get a bit angry about the unlimited beverage card. This is a good deal if you plan on drinking a lot of soda. It sells for like $18 and lets you have soda by the glass from any of the bars or in the dining room, otherwise you have to purchase soda. Well, apparently it does not work on the day of embarkation. Yes, they say it is good for your entire cruise; I guess they mean that BEFORE the boat gets back to port. I was annoyed to say the least! My shipboard charges for 2 were $1000, not counting $1500 of Art from the art auction and they wanted me to buy a diet coke on the last day, PLEASE! Its not the cost, it is the point.
Entertainment: Some great/ some just OK, depends on your tastes. If you want Cirque du Soleil, go to Vegas, not a Carnival cruise ship. I personally hated the music in the disco (as did many people I talked to, but there was many things to do, sometimes making it hard to decide.