They are a fun gun to shoot WHEN/IF they work. Quality is pretty good and the "junk" comment would apply to their reliability. As you noted, VERY fussy about ammo, make sure it cycles and extracts properly. (I had extraction problems) It seems that lower powered ammo is better.
Expect to tinker with it to get it working, especially ammo and mags.
I still have one, it is a great looking gun and a good copy of a Luger, but didn't/wouldn't pay $250 for it.
Manufactured from 1964-1971.