The thing about the D810 (and all modern Nikon's) that separates it from other cameras that I've tried is the dynamic range. I've preached this gospel before but it never ceases to amaze me what I can do with a file even in lightroom which isn't the best when it comes to handling the Nikon NEF (raw) file. Below is a file I shot while out with fellow Nikon shooter Roni Chastain we explored a spot that went from bright sunlight outside the broken doors and windows to near pitch black in the rusted shadows. 

Simply by pulling the shadows and black in LR CC i was able to bring the following image out of the straight out of camera raw file that is below it. Truth is i should have underexposed the image a little more so that the outside was less blown out - but that mistake is mine. Not the camera. In the past when I tried other brands the shadows would be noisy mud with no detail. With my Nikon I know that the detail is there so I expose for the blow out so that I have detail all the way through. 

Website DXO compares the D810 to it's top competitor and shows the difference. People will say that DXO is biased. Maybe they are but no one that ever shoots both in raw can say that their is not a significant difference. Years ago I would have made a poor attempt at HDR and shot an image for the shadows and one for the highlights and pasted them together in post but the "look" is never right. Not realistic at least for someone like me that doesn't have extensive capabilities in post production.

 For photographers that demand the most from their images and shoot in the raw format I think it's an easy choice.