We cruise a lot of lines, including Carnival, but this cruise was definitely among our least favorites. The 3 star rating is in light of the fact that we enjoyed some of the entertainment and the ports. Also, the weather was wonderful, so it was a nice getaway.
First, to us, the food and dining experience was definitely not up to the usual Carnival standard. Many of the dishes were quite bad (looking at you, Penne Mariscos). And the MDR service was the worst we've had on any ship. You had to ask for everything and that didn't mean you'd get it. The biggest struggle was getting coffee to go with the dessert course at dinner - I think due to the fact that you now order dessert with the rest of the meal so it's just another thing for them to bring out. However, one breakfast we had a very good waiter, who reminded us of the better Carnival service we've enjoyed on other ships.
The food in the buffet was somewhat better, but as others have commented, there wasn't much variety and often long lines. The pizza was quite good, but I don't eat meat and they seemed to make mostly pepperoni. The one time I was able to get a cheese slice, it was really good. Also liked the sometimes-available gelato.