I have given one example with the SKYTRAX survey.
I am fully aware that customer feedback in any form is subjective. But then, there are several ways to eliminate the 'subjective noise' in order to get to the hard facts. That's used in professional surveys.
I have my own experiences with several airlines but I don't dare to make any sweeping statements because my experiences only cover such a small amount of flights that this is nothing that can be used to derive any general view.