Have two classic MOSFET amps.
An early 80’s Kyocera (65wpc), $1000 retail. And I have an early 70’s Sansui AU-9900. Both have 4 MOSFETs four channel. Both sound entirely different.
I bought the Kyocera new back in the 80’s, I had compared it to McIntosh, Aragon, Adcom, NAD, Forte and some others that were popular at the time. It was the overall winner for sure. Tube like? Well, sort of I guess but only in the sense that it wasn’t harsh like most solid state amps were and are. Its bass is good, typical solid state in nature, its highs aren’t overly bright and harsh and its midrange is its strongest point which are warm with a large soundstage. Really great amp that no body knew about.
The Sansui classic is definitely tube like. It has a mid-bass bloom that is very noticeable, its top end is somewhat rolled off and its midrange is deep and dark. Definitely a lack of detail overall.