McIntosh- Sweetest, Smoothest sounding Solid State ?

None that I can tell, but others will have a different opinion. The Mac amps that I have tried without autoformers sounded thinner overall, and less solid in the bass.

It mat not have the big fancy dancing blue meters, and lacks any kind of bells and whistles, but the Sugden class A solid state amps sound sweet indeed.

Yes, the Sugden amps have an organic sound, especially the Masterclass. 

Since March 2020 I’ve been working from home and have music on much of the time. I’m actually thinking about getting a Sugden A21SE to use when I’m playing music while multitasking. My tube amp has a fairly pricey compliment of tubes and I cringe thinking about reducing their remaining life while not always listening intently.

...my other thought is a Pass SIT-3 when not running my tubes.