Needed: Honest Advice on high-end amps- either mono or stereo

Now, if you’re going for the Sound, spectacular the imaging from ceiling to floor off onto the side walls. Not natural in musical, but absolutely incredible. Then the Burmeister Boulder and some of those other brands are for you.
 

@ghdprentice I respect your opinion and usually we’re aligned. However, I have to disagree with you here. I don’t have extensive experience with Burmester but heard two full burmester systems and they sounded very natural to me. They actually sounded slightly warmer than I would like. 
As to Boulder, I’ve had my 866 integrated for over a year now driving Wilson Sabrina. The Boulder amp sounds like the components feeding it. It’s not musical with cold and sterile DACs, but will give you goosebumps with a musical and engaging source components. It sounds incredible in my system fed by a Meitner DAC or a good analog source. Very natural, musically satisfying it reproduces music as natural as it was recorded and gives you a true picture. Not overly and hyper detailed, warm enough and vibrant enough at the same time. I would love to have a full Boulder stack.
Or a full ARC stack (huge fan). Or VAC. 
I don’t care much for McIntosh. I think they make gorgeous looking gear that homogenizes everything you play thru it. It does sound good but I just wouldn’t buy a McIntosh amp - not my cup of tea overall. 

I never heard a D’Agostino amp but heard plenty of Krell and love the sound of his amps from his days with that company. 

Also, let’s not forget Pass Labs, Luxman, Accuphase, SimAudio, Coda, etc. All make great components. 

@ghdprentice +1  I suspect some here spent more than that for their speakers alone. As far as I’m concerned, good for them. If my circumstances allowed, I would too

There all good amps if you can afford them. I am lucky enough and worked hard to afford some of these amps but bought them all used and have had good luck. If music is your psychiatrist  then enjoy it. Music releases the dopamine in the brain that has a mu and euphoric effects.enjoy the search.

@OP What specific advice are you looking for?

I happen to agree with Viridian. Audition, audition, audition. No one knows better than you what you like. And that really applies to pretty much everything. Sure, get some suggestions, ideas and general guidance, but at the end of the day... does the music you're hearing move you? Like most everything else, do what makes YOU happy.