I listen to all types of music but classical predominates. Consequently, massed string tone is most important. In evaluating a new component, I start by loading up a kind of string tone test CD of mine. It’s a recording of Eine kleine Nachtmusik by Academy of St. Martin in the Fields, Neville Marriner, Decca 1973. It is an excellent recording to scare up any hint of stridency. It is not necessarily the best sounding of masses string tone but more of a challenge to get it right. By right I mean an absence of any kind of shrillness and the presence of string texture.
My least important (but still important) is low bass response, below 100Hz approximately. This because low bass response is so room dependent and rather idiosyncratic. What I hear I believe is the interaction between the recording and my room.
At least in my experience if a new component excels in massed string tone, just about all the other sonic qualities will fall into place.
Just my opinion.