I don't know many people who can compare different playback set-ups with such clarity when they were unable to A/B the two digital playback set-ups using the same amp/speaker combo.
I know that I would have trouble playing a CD on my upstairs system, taking it downstairs to my second system, playing the same tracks and declaring with certainty that there were major differences between the two. My musical memory is good, but not that good. It works when comparing different CD masterings, but not the same CD.