I'm somewhat of a different voice. The original poster sailed aboard a Fantasy class Carnival ship. While I haven't sailed aboard any Carnival ships because of their style and decor, there are quite a few veteran cruisers familiar with Celebrity who report that the newer Carnival ship's cuisine meets or exceeds Celebrity's. Also, that Celebrity's cuisine is declining and steadily where Carnival is going the other direction. These days, I would say, do not expect great food on Celebrity. Expect standard banquet-quality "cruisine".
As far as the cruise. I don't know. At one time Celebrity was marketed to a somewhat discerning cruise passenger that expected to dress for dinner and desired it, didn't ask questions about smuggling liquor aboard, and the like. The ships were mostly fill of Celebrity cruisers. Now, the ships are marketed toward a general mass market passenger and Celebrity has become a value line. You are likely to find a lot of general cruisers onboard, they could be on Princess on one cruise, Carnival the next, RCI the next and Celebrity the next. Some don't even care what ship they are on. Just that they have a balcony and a large casino.
I don't know if any of the major lines truly offer a "better" overall product than the other anymore.