Overall, the sound quality of the Tristano set is not pleasing. One full disc (#1) and portions of a couple of others have really poor SQ, but the rest is OK. The SQ of disc 1 is so low that I can't really enjoy the music and seldom listen to it, but I find the other discs enjoyable.
I did not expect great sound quality given long-dormant "Personal Recordings 1946 – 1970", and I'm sure Mosaic did as good a job as possible with the source material, but the low points were somewhat disappointing. I know a Tristano enthusiast on another forum (not Hoffman) who disliked the set due to sound quality.
IMO the Tristano set was a "must issue" for Mosaic, that kind of thing was ( / is?) their raison d'être.