Sometimes, the New Christy Minstrels get put down as a little vanilla. But their first 5-6 LPs are a rollicking good time. Once they started doing contemporary pop tunes on LP, things didn't go too well.
But what had happened was that Sparks, who owned the NEW concept, sold it to a couple friends who basically wanted to maximize profits and run the group as a touring machine, no more creativity or original songs, less time spent on the LPs, revolving door of members who did not gel as well. And the longtime members who stuck it out saw none of the profits. Unique voices like Barry McGuire went solo. By the late 60s, the Christies were still singing like it was still the early 60s which unfairly colors their reputation to this day.
MBarnum, there is a fine 2-disk collection on Collectibles which covers a lot of the great tunes from the NCM's best years and has excellent liner notes. The individual LPs are also available usually 2 per disk.