I think his point was that since one speaker creates less resistance than the other electrically, that it would appear slightly louder than the other if you don't move the volume dial to compensate.
Since it has been shown that in A/B tests people tend to always prefer the louder speaker, a "Strict" A/B test would have to include calibrating both sets of speakers so they play at the same volumes to make it fair.
That being said. The best choice is always whatever makes you feel the best within your budget. Enjoy!
