My experience largely mirrors heavywalker. I have had eventual failures with all brands I have tried.
I have been perhaps most disappointed by Zeiss Conquest. I put a 3-9 on my dad's 6.5x55. After perhaps 50 rounds it would not hold zero or track properly. Returned it. After a long wait (can't remember) they sent a new 3-9. In less than 20 rounds the new one not holding zero or tracking. Sent it back. After a long wait, I called asking what is going on. The lady looked up the records and confirmed that both scopes failed. I suspect the second one sent was a refurbished because the serial number was lower than the first one I sent in. She then sent and new HD5 which has held up well.
The next problem is that while I was waiting for dad's second scope to be fixed I bought a 3-10 with z600 recticle. Well that one survived about 100 rounds on my 270 WSM and died. It is still at Zeiss.
The glass is beautiful to look through, I really wished they would work. The mechanics just don't hold up.
I will not buy another Zeiss.
