Audio Research versus McIntosh tube amps: anyone experience or compare both?

I don't like it when people make a post that doesn't really answer the question asked, and I will start by admitting no McIntosh experience. I am, however, recently back and forth between a Ref 75 and the XA-25, and I actually find the XA to have more midrange warmth than the Ref 75. I really like them both a lot - Ref 75 edges out the Pass on soundstage, and Pass seems just a bit warmer/fuller in the midrange.

At least to my ears , if you are looking for more warmth in an amplifier as you suggest - I don't think that the Ref 75 will scratch that itch over the XA-25.

I at one point I had both a Ref 75SE and Pass xa25 in my system. I concur with @chcook's statement " I actually find the XA to have more midrange warmth than the Ref 75. I really like them both a lot - Ref 75 edges out the Pass on soundstage, and Pass seems just a bit warmer/fuller in the midrange." I will add that I thought the Ref75SE had a little blacker background.

Let me add this: my system photos feature a few of an ARC amplifier - a vintage VT100 purchased from a friend last year.  It’s been hot rodded with new caps plus kt 120’s and sounds very good in my set up - better than I had expected!  But it has two issues: a fan which I dislike ( audible) and it’s a PIA to bias (never mind the cost of replacing 16 tubes …).  Hence my thinking a more modern, easier to deal with tubed unit might do the trick.

Anything preowned would of necessity be bought without an audition in my set up and thus it’s a bit of a guessing game.

Other suggestions welcome and thank you!

Pick up an ARC D-79A or D-79B.  Even used, a lot of people think it was the very best amp ARC ever produced.  

"Pick up" was used figuratively.   

I have an audiophile friend who switched from pass lab XA160.8 to ARC ref250. Paired with ARC ref10 pre amp he and I just love how they sound with Magico S3. If you like details and “fast” response with a little tube bloom then ARC is one of the very few maker who can make this balance meticulously. Macintosh IMHO is more “classic” tube sound : “musical” (=slow transient response so not too much details ) but each to their own. 
disclaimer : current user ( and big fan）of ARC ref10 / ref 160 mono mk2 , I had used CJ / Counterpoint / Jadis / Mac / Kondo / Manley in the last 25 years and these are the best tube pairs I had ever used.