Thanks to everyone who has replied so far...much appreciated.
As far as difference in the SQ (of music) among different brands of receivers, i know there IS an audible difference, at least among some brands. I have taken different brands home and tested them before. Usually with about 3 other people, using different musical sources, and one of us flipping the cables back and forth, while the rest of us sit with our eyes closed, so we didn't know which one we were going to listen to.
Over the years my comparisons were (i think):
Except the Carver/Sony comparison, the differences were always subtle, but noticeable, even to the ears of my various ex-girlfriends, who cared less about sonic quality than i, until they were forced to sit down and give an opinion.
Now, i'm not saying EVERY brand has a noticeable difference from every other brand in sonic reproduction. If i had compared Marantz and HK, maybe i wouldn't have heard a difference. Maybe Onkyo/Denon would have offered no preference to me. Maybe it's just with the particular brands i chose to compare. But with the ones i DID choose, i noticed a difference.
But agree or disagree with their preferences, most people can make the same evaluation of sonics, only with different words. Denon lovers always described their receivers as "accurate, clean, loud" etc. People who hate Denon may call it "sterile, shrill, or tedious." But friend or foe, Denon is never described as "warm."
In addition, not everyone has the same level of discerning taste in audio. Whether it's from lack of exposure, or just not having a good ear, not everyone will notice the differences. I have friends that are really into wine. No matter how hard i've tried, i can not taste "a hint of oak and orange peel" in my merlot.