Roy really brings up a good point, build quality and reputation is one thing but only your own eyes can truelly tell you which one is for you. My Dad and I argue all the time over optics. He hates anything Swaro. Says they are junk. I dont agree but I think the Swaro for some reason just does not work for him.
Spend some time looking through both. Take as much time as you need. Your spending good hard earned money so dont let the monkey behind the counter intimidate you by being impatient. Take them outside and look around at many different things at all ranges. Do each scope at least twice before making your decision.
I will say, from what i have seen with my eyes, the Zeiss is the superior of the 2. I have not got to spend much time behind a Mark 4 Lup tho.