Powell wrote:

High level "midrange detail"... is not available at three
times the price point base on manufacturing costs to
produce really high level detail. Consumers have
little choice but to comprise in one form or another, in
the low end market.

Have you used an FMR RNP?

OTOH, I use a Audio Power conditioner with the MPA
Pro and find the midrange accuracy to be suitable for
critical work.

Critical is as critical does; there's a man posts here who considers his
GML pre apt for voiceover work. It's also apt for just about any other
"high level" music recording application. I am uncertain why you think
detail is improved by the power conditioner unless your source AC is
pretty screwed up.

If the sound deviates from anything but a flat response
then preference comes into play.

I recently enjoyed a casual comparison of four truly excellent preamps
(Gordon Model 3, Grace Lunatec V. 3, Great River MP2-MH and Millennia
Media HV-3D), all with admirable linearity to 100 KHz or well beyond,
all with admirable phase coherence and extremely low noise floors
bumping theoretical minimum, and they all sounded different. _Flat
response_ is a single aspect of performance and not necessarily
indicative of any unit's sound.

--
ha