What is the best solid state amplifier you have ever heard?

I do really like listening to the Ayre MX-R Twentys as well.

The three that are all in systems that are used regularly with widly various components/cables/interconnects/ pre(but all tube pre)/sources/speaker combos are:
Bedini 100/100 in system at my office
Levinson 23.5, aecond system
Pass 260.8 mono's, main system

No thoughts to any future upgrades 

yyzsantabarbara

I have not heard the m-900u. As good as the 509x is I am sure I will instantly want it...but from what I have heard, it really needs to be driven from the c-900u preamp to totally manifest its magic. This is not in my budget at this time. That being said I could step up to the m-900u and use my dac as pre for a while...but not sure if I’d actually be in a degraded state from the level I have now...which is the best system I’ve ever assembled in this often torturous journey. I recently came from pass x250.8 and xp20 combo. Excellent gear no doubt, but there is more realism and soul, to me, with the 509. I remain sort of in a state of disbelief as the weeks roll on. Thusly I think I’m better off pipe dreaming about the 900 level stuff but in the meantime totally enjoying this wonderful integrated.

There isn"t......

@stevea11757 
Are the  Pass 260.8 monos really good - i.e., tone, body, drive?  They are sort of on my short list of amps to consider but would be a downward move in power for me.  Are they warm, lean, neutral?  How about resolution?  Do they have a lot of drive for inefficient speakers....not crazy hard to drive but like 86dB efficiency, a minimum impedance of 3 ohms, and a fairly innocuous phase angle?  I would appreciate any feedback you care to share.