McIntosh had a difficult time moving from tubes to transistors, As a matter of fact McIntosh was one of the few companies that continued to use tranformers with their transistors power amps. Marantz never really made a good transistor pre amp or power amp.

How good is Mac? today well it all depends on what type of music you listen to and the speakers you use. Remember in the golden age of audio , music was softer and more detailed than today. Speakers though less focused was more detailed as well.
Times have changed , Mac and Marantz was not really designed for rock music.

Analog or records are more detailed than digital , digital has more dynamics.
The old tube Mac and Marantz was designed in the days for analog. Listen to a Sinatra recording using older equipment and listen using the new digital equipment.
There is a difference. Listening to rock the digital music will favor the rock.

Finally I have owned a McIntosh MC275 for 45 years and it is still sounding great.
But than I don't listen to rock. Those who dislike Mac. equipment or rock listeners.