I'm going to break this down into some categories.

Your thoughts on each category.

Tube amplifiers - Does it really sound better for mid to high freq?
I have no opinion.

Consumer grade amplifiers - Technics, Sony, Aiwa, JVC, etc.
Is it junk ?, I think so. Weak power supplies and output stages.

One step up from consumer grade amplifiers - Denon, Onkyo, Marantz,
Elite Pioneer, Yamaha, etc. I think this stuff should be the normal
consumer grade stuff, it's worth the money paid I think.

High-Fi/low end exotic - Parasound, ATI, Adcom, Anthem, B&K, Rotel,
etc. I think some of this stuff starts to resemble good circuit
design with beefy circuits (transformer/output stages), probably
worth the money paid.

Exotic - The field is wide open, Krell, Passlabs, Levingston,
Conrad Johnson, Bryston, Jeff Roland. blah blah blah ........ blah blah. I find it hard to justify paying $10k for 200w/ch amplifier - heheh I'm sure they are fine amplifiers, construction, circuit design, but god-aweful expensive.

Prosound - Interesting, seems to give a nice bang for the buck.
Crown, QSC, not sure about this but Cinepro, who else?
Sonically, what is wrong with using these in a home stereo ?

Esoteric - Bob Carver's Sunfire - The controversial designer
has done it again with his new innovative tracking downconverter
(patented) power supply. I read his patent and I'm amazed at the concepts.
My real issue is whether this design can power subwoofers as well
as a similar amplifier in it's class. In theory, it should outperform
many amplifiers in it's class for mid to high frequencies due to
it's high dynamic power capability (handing transients).