@gpgr4blu excellent summary. You've actually experience all of these amps so I really value and appreciate your opinion. I'm leaning Ref 160M since I know I won't have issues getting them serviced, plus they're gorgeous, auto bias, longer tube life, etc.
I've heard some people have had issues getting Lamm's serviced (they claim they can't get a hold of anyone). Vlad was a genius but since his passing this year I worry about customer support. Their website has been "under construction" for some time. That said, I've heard nothing but good things about the sound.
@adg101 maybe bright isn't the best descriptor. More forward and top heavy. I applied a 1.5dB rolloff above 14kHz via Roon and that helped. I've treated first reflections with GIK panels after consulting with them, that helped tremendously. But remember, I'm coming from Harbeth's, so going from zero fatigue to some fatigue seems like a stark difference.