Can't comment on the Nikon, but I have quite a bit of experience with the Zeiss Conquests and Leupold Vari X III's and limited experience with the new Leupold VX III. It's no contest in my opinion, the Zeiss Conquests are just plain better. They offer better low light performance and better resolution in all light conditions. The 3.5-10x44 Conquest should be an excellent scope. I don't have that particular model yet, but it's just a matter of time before I buy one.