I also think these albums are among the best, for the reasons listed at the beginning of this thread. On paper they might not look like anything out of the ordinary (and I passed them by for a long time on that assumption, that it was probably just another blowing session by a good group) - maybe that's one of the reasons the sessions really stand out. (And they are not necessarily as familiar as the live recordings of - say - Miles, or Coltrane, or Bill Evans, all artists that we have come to expect such a high level of musicianship, whatever the setting.)
Just came across the "Dowbeat" reviews of the first two. Volume 1 got 4 1/2 stars (it would have been higher, but the reviewer though Kamuca was having an off night) (?!?!!), and Volume 2 only got 2 1/2 stars (think it was John S. Wilson - he though the tunes went on way too long, to the point of being unbearable.)