The way most people do it is with an A/B switch. I’ve found that the best way for me is to blindfold myself, have someone switch one on without any information given and then demo both. This way you don’t get the whole placebo effect. A lot of times the one that sounds better is the one you WANT to sound better. I’ve had some cheapo 90’s units that sounded better than my nicer 70’s era stuff that most people would argue are trash.

That being said, if it sounds better to you then it’s better. So really, go with what your ears are telling you.