Whenever you buy a new lens it is wise to find as much information about the lens before parting with any money. The Zeiss Otus 55mm Lens has had plenty of reviews on the internet including a very comprehensive comparison with similar Lenses on this very Forum.
However we are all different in photographic skills, attitudes and applications of the lenses for certain subjects, and at the end of the day opinions are clearly subjective.
I think the only way to test any lens is by using the lens for your personal intended use, does it meet the criteria you bought it for, and can it improve the final outcome.
My experience of this lens on a D4 and this is early days so far, are the colour is richer and in low light situations the lens seems brighter and easier to use. Ok it's heavy, It just slightly bigger than a Nikon 24-70 2.8 Lens. The big question is yes, it's manual focus, so for some photography this lens would not be suitable. Zeiss clearly state this in their sales blurb. But if you appreciate quality and enjoy the feel of a hand built lens, it is a pleasure to use.
Manual focus? Well in the old days that's all we had, so going back to it was quite novel, having said that the Otus lens seems very easy to manual focus and after just a few days it does not become a problem, plus it has a DOF ring on the lens.
Some photographers will say that this lens is best suited to the D810, probably so, but I am a prepared to wait till Nikon bring out a D4X/D5 with even more pixels than the D810 Then this lens will truly show it's quality.
Camera, Lens and Tripod and a few other Bits