To be fair....I consider exact centering the star on the disc to be perhaps too stringent. My own criteria is the focused star should be superimposed on the disc, not necessarily centered.
Now you tell me. The focused star is certainly superimposed with my sample.
As far as the rugged build...I think it's possible to build binoculars That are essentially "bulletproof" (and maybe these are) but still if you are going to use various eyepieces, especially high power, it would be nice to be able to tweak the binoculars to correct eyepiece centering errors.
The build is solid. The magnesium shell seems very rugged and yet it is lightweight. I guess time and experience will tell the tale.