If you are serious about your lenses and loupes, microscopes, telescopes and planetariums, then you buy Zeiss.
Zeiss microscopes and binoculars are indeed very fine , but their single lens loupes are no better than B&L loupes though they cost more in the US. In a loupe, the price differential isn't worth it, IMO.
Multilens devices are a different matter, though I don't know any coin collectors who use anything other than a pocket loupe or handheld magnifier.