But here are my $0.02 for what it’s worth.
I very nearly got some non Twenty MX R’s. I ended up with the X350.8
I have not heard the Ayre MX R Twenty but have heard the VX R Twenty in a demo system, paired with the KX R Twenty, driving Aerial Acoustics speakers. The dealer A B ’ed them with some Pass XA 200.5 monos. The Pass were driven by ARC Ref 5 SE. In that setup, I preferred the Pass and ARC pairing overall. It sounded fuller and more musical. The VX R Twenty was more articulate and refined. There was more inner detail. I wouldn’t have called the VX R Twenty lean but it did have less body compared to the Pass.
I had my initial shortlist down to non Twenty MX R’s and a X250.8. In my previous system with Dynaudio speakers and a Cary SLP 05 pre, I preferred the non Twenty VX R to a Krell FPB series amp. The highs were less strident, it was slightly rolled off - in a good way. In another demo system, with Avalon speakers, I also preferred non Twenty MX R’s to a D’ Agostino Master Power Classic. The Ayre had a better musical flow.
However, the deal I had on some non Twenty MX R’s fell through and I ended up getting a X350.8. The Pass was more full and visceral sounding than the Ayre with great timbre all throughout. The bass slam was impressive - not so much as the older Krell type slam, I don’t think anything will beat that - but more textured and less of a one note presentation. If my memory serves me, the treble is smoother and more extended than the X 0.5 series, where there was still some hardness and grain in the highs. However, the midrange is not as warm as the X 0.5 series. Vocals are more clear and natural sounding but the midrange emphasis that made them so alluring on the X 0.5 series is not so much there.
Overall, the Pass will probably have better grip and control of hard to drive speakers than the Ayre will and give you better bass slam and a fuller presentation. Although Dali Epicon’s aren’t as difficult a load as say Dynaudio. I have heard them successfully driven by medium powered tube amps.
Strangely enough, one of the pro’s for the non Twenty MX R’s for me was also the smaller form factor and easier transportability you cite. The X350.8 is big and a heavy 2 person load.
I could have lived with either the non Twenty MX R or the X 350.8 in my system. I can only imagine that the Twenty versions are better, especially if they improved the bass performance from what I have read. I wouldn’t describe either as tube like as many do. At least not in the way Conrad Johnson amps sound - that is another sense of harmonic richness that no solid state amp can give.