I had the PCjr versions of KQ1-4. To me, they blew every other game on every other system away. Greensleaves never sounded better than with those 3 polyphonic beeps in KQ2.
I remember the “hate” letter I wrote to Sierra when I bought KQ4 with the new graphics engine…my glorious 16 color PCjr graphics support was dropped. They sent me a version of KQ4 using the old graphics engine, and I was back in heaven.