Did you seriously get a number of receivers together, on the same speakers, same source, same room, to compare? You level matched them too, right? I assume it wasn't blinded, because my jaw would drop if a high end store set that up for you, on receivers of all things (not super pricey separates).
If you did the above, which receivers did you compare under such circumstances?
If you didn't do exactly the above (same room, same source, same speakers, level matched), then your comparisons "by ear" are meaningless.