Fun review to read Ray. You write just the way you talk in person. I can almost hear your voice. Maybe if I wiped the screen with a good wipe....or changed to a linear PS from the dumb switcher....
I also like the (tm) on the twinz. Funny as hell!
Doesn't work for me to do a long long session for comparing. With a good system you can set down and enjoy for long times. But when you are trying to really analyze and listen careful, you fatigue and get what I call "cooked" pretty quickly.
I've worked and worked and worked on sound (I have an advantage in sound changes from purposely manipulating sonic charateristics!) and be pretty satified. Get up the next morning and first listen, ARGH! Easy to hear something I didn't before. So over time, I've found smaller sessions works better and over time you can pick up on things with greater clarity.
That's why I think it works so well to change something in your system and then leave it alone for a several days or even a week or two. Then cut back over to the original and see whether your previous impressions hold. Yes or no, then listen to the original for a while before you go back to the new. By now, you can start to sort out over a number of tunes, the real differences. It helps eliminate a bright sound from having a positive jump out at you as "better", instead of as unnaturally bright. Peaks are easier to hear than dips. However, that's an eq way of thinking of things which is not normally ever what we get from component changes. What changes, to me, is a character of each note and the background. More like a gritty substance on an otherwise clean surface is the way I think of for the character. That can be from mids on up. Bass has it's own vocabulary of sonics.
Some of that vocabulary thing is what you've written about here. Average people don't have the words to use to describe the differences. Some say, as here, that they know something changed, just not how to verbalize it. Some people don't even listen close enough to hear the changes either...that's not unusual. Audio people on the other hand have read enough reviews to know words to use. Sometimes a word used by somebody else may mean different to you...so beware of that. Asking questions to clarify what someone is saying can really help to avoid misunderstanding what someone is trying to say.
Quick comparisons can have value...sometimes. Quick tends to mislead. Kind of like a bar pickup the next morning I suppose. Or so I've read.
Keep enjoying the learning Ray. Don't let it be too much. Look at is an investment with potential to raise the level of enjoyment over the long term.
The year of the 10th Carverfest! Be there at CF2016!