Circa 1999 I studied Minix in a operating design course, but in the same way we studied Amoeba or Mach; in fact we used a pre 1.0 Linux kernel for practice (I don't remember the distro, it could be custom), and it was small enough to understand the different parts, hack, compile and run.
"Operating Systems: Design and Implementation" (included Minix) and "Modern Operating Systems" are great books and I think is because of them that Minix is relevant in OS teaching (specially OSDI, although I enjoyed MOS too).
EDIT: typo