I think the general comments on sound quality go more to production than the music. JJ was a down-home kind of guy, probably more known by musicians than the public for most of his career. His music is pretty simple & straight forward, and as noted he had his own recording studio, and production was in the same vein. Production-wise the SQ went up probably starting with Troubadour, carrying on thru from there. Not sure what may be available in the way of remasters at this time, or if there are SACDs available as yet. I imagine in time there will be, but I wouldn't avoid any of his releases since none are bad recordings imo.
I don't know that his early work would match up to the Blue Note recordings quality-wise, though the initial CD release of Kind of Blue was pretty rough. The first few recordings pretty much sound like a group of guys sitting in a room playing music, much like you'd hear in a small club, not what I'd imagine as a studio. They are laid back, and not terribly dynamic, but the music is pretty laid back as well. Good luck with your search, if I run across anything that stands out above the intial releases quality-wise will post for your info.
