I have owned the Nikon and I sold it due to lack of use/need of funds. I am planning a pretty extensive trip in the western part of the country so a wide lens is mandatory. The Nikon was pretty good, but I think I will be going with the Zeiss this time. It captures detail/color/contrast better in my opinion. I have to admit that I was unimpressed with the Nikon's corners, but I think that is a result of just how awesomely wide it is. Compromises are mandatory in photography. Color-wise, the nikon is very good. Overall optically...I guess I would give it an 8/10 using my Zeiss 100/2 as a reference 10/10. It is pretty sharp, it has good contrast. I don't think it delivers the "3D Zeiss" look that a lot of people appreciate (myself included). This is a difficult choice because if you are willing to sacrifice versatility you get absolute image and detail quality...if you can sacrifice a little (not much) IQ you get absolute versatility. The nikon is a large lens, but it is not as bad as some people make it out to be. One more thing to consider is the availability of filters. Zeiss can handle filters like a champ, Nikon can handle 0 without some apparatus. The Zeiss has a very close MFD, which can provide some interesting perspectives. The Zeiss lens is a little smaller but is very solid. The zeiss lens with it's hood on just looks very "darth vader" to me. The 16-9 adapter can take some time to arrive, but I understand the newest one is pretty solid. I had a V1 adapter and it was alright. I know people will say "oh these are totally diferent lenses!" but for a lot of us they fall in the same category. We are looking for something wider than our 24-70/105L lens. Versatility or absolute IQ? The TS-E lenses are also something to consider - they are excellent as well. Good luck with your selection, you can't go wrong. FWIW you should check out the Zeiss 21 thread, look for snowboarder's stuff. There is one photo with a large fin-like rock formation at sunset that convinced me that the Zeiss was the lens for me...it's probably the best photo I have ever seen from one of the best landscape photographers around. Good luck!