Which mono power amp would you choose and why?

@alucard19 - not sure what power you are looking for but watts mean nothing.  I just finished upgrading a Spectral power amp.  To me it was nothing special and rather boring in stock form.  Once upgrading the amplifier, it was another level that I would even consider buying one and I am a tube guy.  In my 20 + years of modifying gear, the upgrades sonically take components to a entire different level that the stock products offer.  You may want to consider something like that and have it upgraded.  Happy Listening.

I have a pair of Ampzilla 200 wpc monoblocks in my exercise room system. They have of course been modded by Doug Jesse of ASi Teknology and sound sublime. These occasionally show up on the used market. I have also a pair of JC1 monoblocks that have a less liquid slightly grainy sound. I also have Canary 140 wpc monoblock tube amps, modded of course, that sound very nice.

@jaymark Is your CODA #16 as powerful sounding as the other amps in your possession? I am also thinking like the OP to buy something with massive power over refinement. The CODA #16 is my idea of a refined amp the Michi that I referenced above should be an exciting amp but not as clean on top. I have heard both lines so that is where this opinion is based on.

I had a very fun 1+ hour demo with KEF Blade 1 and Hegel H30 monos in a big room. It also was not as clean sounding as the CODA #16 but a super fun listen. The H30 and Michi M8 are identical power wise. The Michi X5 I heard sounded a lot like Hegel, Class AB sound. Slightly grainy, with the Michi maybe smoother.

I just got off the phone with a local audio store and they said they will be getting the S5 or M8 in the shop in 2023. So, I am going to wait to hear these before I buy anything else. Until then a Peachtree GAN1 amp is coming in next week to hold me over.

@yyzsantabarbara the Coda sounds just as powerful as other amps that I have or have had.  The 150 wpc with 100 of them in Class A leave me wanting for nothing.

Potentially consider Threshold - you may be able to get some SA/1 monos re-capped at or below your price range.  I believe a former employee still services/updates them.  Think these would be hard to beat for the money.