So let me contribute my own personal tastes.
I find CX F food disappointing in longhauls, especially Chinese food that is usually mediocre and bordering tasteless. Would definitely rank BA F food above it. In comparison, CX J food (longhaul) is good relative to other airlines.
But F is luxury and the overall CX F experience is great. I must confess that I often order BOTH the Chinese set and one western main dish. Remember that you can order anything on the F menu.