All cruise line have budgets, each department has different budgets on Royal carribean you might eat in the buffet with low quality plates and silverware and on Celebrity Which is owned by Royal Carribean) you will find china and nice silverware. Example:
Carnival spend less on food and more on activities....so one could expect to find more things to do on a Carnival ship but eat a lesser quality of food. After all the name says it all.
Royal Carribean has one of the lowest budgets of all the major lines for food..at best it is edible...
NCL has really great shows on board but lack in other areas...
Celebrity was once know for very high quality of food, service for the most part is good. However in recent years the quality of food has declined somewhat but is still better then most other major cruise lines.
In the Mass Market cruise lines you will find on every line that they excel in one area but lack in another.
The higher end cruise lines excel in food and service and offer a more relaxing refined experience.
You truly get what you pay for.