Among musicians there is always dialogue about favorite composers and the like. Almost everyone has the same "A" list, and that "A" list intersects extensively with the "A" list of people who spend more time listening to music than playing it (or do not play at all). I do not need to list those composers here: you know who they are.
During the 12 years of my professional life programming music for a radio station, I made a serious effort to treat A-list composers as equals to the rest of the "pack" that was available on recordings. That self-appointed task became rather easy when Marco Polo, a subsidiary of Naxos (a small budget label during the early 1990s) started offering really fine CD recordings of non A-list composers. It didn't hurt that I had been friends with the founders of that label in Hong Kong, so I received the whole library gratis. The Naxos library and the obscure small-label releases I got to review for the American Record Guide moved our library to the cutting edge as far as non-A-list composers. During the late 1980s and through the 1990s NPR stations spent a lot of time playing "greatest hits" by Rodrigo, Pachelbel, Gershwin (non A-list composers) many times per week, and single movements from larger works by A-list composers. I couldn't turn on an NPR station and hear anything I couldn't identify in the first couple of seconds, but my station, which had a library of only excellent performances of music by composers who were often new to me, offered listeners a challenge to listen to all kinds of new music (particularly "old" new music).
It is very easy to hear something that sounds a bit like (Robert) Schumann or Brahms, for example, and consider it "second-rate" Schumann or Brahms. It is very easy to write off that non-A-list composer as someone unworthy of your attention, and in the same breath write off the piece at hand as something less valuable musically than a piece that is by the A-list composer. If you hear it on a recording it is even easier to make that kind of dismissal, because the performance has been reproduced, and will always sound the same. It doesn't get better, though you may become a better listener. When evaluating something negatively we often decide that there is something wrong with it rather than something wrong with our evaluation of it. (In relationship terms it is kind of like the phrase, "It's not you, it's me," which, of course, usually means the reverse.)
I believe in performing well-written music by composers who never made it to the A list (and never will, since the A list is firmly set in the past). I love to practice music by A-list composers because doing so compels me to grow as a musician in order to meet the A-list composer half way. I love to study, play, and listen to A-list composers, but I feel that my "job" performing good music by composers who never made it to the A list is to make the experience of the music as meaningful as possible for the people listening to it, and, in the case of chamber music, for people playing it. If I have to reach a little more than half way in order to "sell" the immediate experience, and to eradicate the necessity for people listening to resort to comparisons with what the piece is not, I have been successful. Perhaps I have to "believe" even more deeply in the music I am playing than I would have to when playing something familiar, but I feel that it allows music to happen in original and unusual ways.