Popular new/used SS stereo power amps under $2500?


Not long ago I began putting together a hifi system (on paper), and with the help of members here, learned I was going about it the wrong way, so I took a step back, and started over.  Meant to keep this short.  Didn't happen. 

Just to say it upfront, I did do searches on the forum and on Google for new/used stereo power amps under $2500 and only found related threads like preamp and integrates.  There were also hundreds of hits, but none visible in the first pages.

About what I'm looking for, and why:  First, the amp is to power a set of Harbeth P3esr.  Sensitivity is low, 83, and they run at 6 ohms. Many have suggested a power amp of 100w/ch for the speaker, from those more familiar with them. I don't know how needed that power is, but it's relatively common for SS to be at or higher than that, so I see no harm it setting the min at 100w/ch.  Some seem to suggest that higher out put amps have some advantages with power reserve for bass or "hungry" speakers.  Their words, not mine! 

That said, any amp capable of meeting those specs or able to run the P3 is a suitable candidate.  The designer even has said on his own forums "any quality amp is just fine".  But let's face it, it's not that easy! Initially, I was scoping out Pass Labs, but those are lofty, worth it, but lofty.  Also, over the top for me. I decided to transfer some funds into the speakers instead that work very well for my room.  With so many amps out there that can potentially power those speakers, I think it's important to include specifically companies with outstanding product and customer support, so I can at least feel confident that if my used $2.5k amp (or less) can be serviced. Hence the reason for a popular amp, vs a limited run or a special. (parts!) 

I am not an experienced audiophile and likely many amps would work well for me, but would love some insight.  Everyone can appreciate a quality build with solid connectors and avoid problems if possible. 

I listen to everything: Electronica, guitar, country 80s/90s, pop, rock. So I guess that would mean a fast/agile amp for long hours. Warmth is good, too! But I know fast and warm are typically mutualy exclusive, I guess emphasis on speed based on the time spent on some of those genres. 

I don't need or want an amp that can "stomp". 

Amp needs:  6ohm.  100w/ch+. Able to power low sensitivity (83).  Can work well at lower volumes with these speakers. 

Sonic character:  agile, fast,..... If possible, warm and musical? Limited fatigue, emphasis on limited fatigue.   Class A is a plus. 

Use:  lower volumes, sometimes moderate, in my small apartment room after work. 

Listening time:  3-8 hours/day
 
Avoids:  limited productions, any amp that needs to be turned up to perform, poor or limited product/customer support, any amp with a short production life, "rare", known risky amps, etc. 

Set up will be:

Rack mounted (active cooling) 

Cambridge azure 851n (it's a start) 
Harbeth P3ESR
Good cables (?)
Power amp.... TBD
Maybe a CD player

Room:  12*12
Apartment

Some amps out there might be, but hoping to see more, are:
Bryston
Classe ca 2200
Parasound a21/23


128x128mplstereo
You have been given a lot of good choices on the amps, but I am more concerned about your room.  With a 12x12 room, assuming also a normal 8 foot ceiling height, you are going to have some strong doubling of modes at 47hz, 85 hz, and 95 hz.  Some money invested in bass traps and careful setup are going to make an enormous difference in the sound in your room. 

Personally, I would consider something like a Schiit Vidar or Parasound A23+ and put the extra money towards the room treatments.   
I own a parasound p5 with a A21+ amp. Driving Magnapan 1.7i speakers. Until I bought the A21+ I used a 40+ year old Mc250 to drive the Maggie's and it did a pretty respectable job with a speaker that normally needs ALOT of power. If you have very efficient speakers and don't mind a tank like amp and want to get the most for your money think about a Mc250 or a Mc2100. BOTH FINE AMPS WITH A SOLID REP. Imho
@mcreyn I actually just picked up a set of Monarchy mono's.  Seems enough people like them for the reasons I think I'll like them and I paid half my budget.  I think most amps recommended here would be great minus anything bright/thin. 

 But your right.  My small room has 3 walls.  Front, Left, Rear.  The right, there is no wall, it simply extends to another room.  The Harbeths (p3) will be against the front, facing the rear.  These Harbeths are ok being very near a wall, one of the reasons I chose them (no port).  The left wall has a standard double hung window.  Ceilings 9ft.  Nothing on the walls but paint.    

Thoughts?
@racamuti Not sure how these got by me, but seems a lot of people love these amps just as much as the Parasound. (maybe?). Pretty much looked everywhere I could to find bad news on them, or at least anything to even mildly dismiss them as a "wanna be" hi-fi mono. But, I couldn’t. Even Pass owners were impressed with these. Initially, I was considering Pass, but $$$. Looked up the website, called them.

I think it was the owner that picked up, sounded like a thick Japanese accent. Had to do my homework and make sure the unit was still in service and parts were available. I asked him if after my potential purchase if he would take the amps in for an inspection. He told me don’t bother, they don’t have issues. Well, I’m still skeptical, honestly, the price is very good for a mono, and yet, some how the reviews are great.
@yogiboy Awesome!  Thanks for chiming in.  I watched your review there, informative and helpful, fills in the gaps for me between the regular and the 40th.  I went with some affordable and warm sounding mono amps, they were half my budget, and have the class A I wanted for the Harbeth's.  100w/ch, I won't need it, but it doesn't hurt.

Thanks for sharing your review!  Yes, your description of who those speakers are for, is actually in MY description for what I'm looking for in a HiFi system!  (that is, come home, relax, and listen to tunes for hours) I see your a valve guy (in the vid), have any thoughts on my monarchy audio SE 100 MK2 selection for the P3? (even though it's SS)  Feel like I'm rollin the dice a bit, not familiar with these amps at all, but a lot of people like them for reasons I want in a amp, warm, not sluggish, transparent...

I couldn't find if you had compared the S400 to the P3, is it posted?  I know im not the only one waiting for that one!