The Zeiss Diavari are great scopes, as are the Swarovs, leupolds are good too (but not as bright as the other two).

I've owned/own all three brands and the only ones i've had problems with have been the leupolds (I'd say 2 of the 6 or so I've owned have been sent back), but to their credit - all problems were quickly resolved by leupold.

Ken - Send the zeiss in for a "checkup" - if you still don't have faith in it, get another scope for the double and either sell or put the problem zeiss on another gun. I understand how important 100% confidence equipment is.