Food likes and dislikes are a personal thing and I believe I would never say one cruise line has better food over another. I also believe that one cruise line may make one particular type food better than another. For instance the best crab salad I ever had was on American Hawaii SS Independence. On Princess I love their pheasant. On Carnival I enjoyed the lamb.
For myself only one cruise line I have been on disappointed me with food to the point that I sent back multiple meals and that cruise line is known for supposedly being the cruise line that is supposed to have some of the best meals.
My point is that to say one cruise line has better food or anything better than any other cruise line totally depends on your own personal likes and dislikes. What is the best for me may not be the best for you.