People can get accustomed to really crappy things and start to consider them great. I am of the opinion that if something sounds great the first time you use it, then it's great. If it takes time for it to start sounding good, then you just got used to the bad sound. It is, however, true that after you get gear that has real specifications which bring noise and artifacts low enough and with an FR flat enough, you cannot observe any differences between different products. As far as sources go anyway.
Still, it is also true that people tend to argue about "house sounds" and gear personality, but this is all extremely personal. It depends completely on what you are prepared to believe, how much you trust other people in general and how impressionable you are. It is not a bad thing. Hey, if it makes you enjoy your stuff more, good on ya! But the only real way to compare stuff is to measure it with things which do not ignore any issue or characteristic.
And the human brain and ear are not such devices. Brains flatten frequency responses because they know what a sound sounds like when it is reflected. Ears do not hear everything in the same way and usually, music is a very personal experience.
Therefore, UI aside, the way I see gear comparisons being valid is to only compare stuff based on objective measurements.
This is what I am looking for.