Just thought I'd add a different perspective.
@BigJimFish give his honest thoughts in his reviews which is very important and appreciated.
I have access to quite a few Minox. Used 4 ZP5 and 4 LR personally. The difference in turrets between the LR and the ZP5 is normal. All LR turrets are easier to turn and all ZP5 are harder. All of them have a stiffer windage turret then elevation. Its not a QC issue from my perspective rather design.
The mechanical repeatability as far as tracking have all been good for me. The spline slop as Jim brought up is a "issue" with stationary turret designs mine have 0.05 mil slop. Maybe i should test again after all the dialing I've done and see if it changed?
I had to send in my LR for a sticking parallax which was fixed. But I also know guys with TT have had that happen too.
The dirt on the ret happens to much in my opinion.
Look through one if you like the ret design get one you'll be happy with a Minox. The ZP5 is my current best. Having said that I have not had a ZCO to play with yet.