I know this has been debated before with subjective opinions, but I wanted to share my experience while shooting with the D810. For a little background, I have used many EVF's, including Leica, Fuji, and Sony. I decided for me, that shooting in low light, or bright ambient locations the EVF's were terrible when transitioning between ambient light and the EVF. I do love the WYSIWYG aspect of EVF, but I can do that with the D810 too, using the LCD. But what really confirmed to me that OVF's can sometimes be preferred was the intimate connection between composing and my model. I was "in the moment", so to speak, during a recent portrait session. The studio was dimly light, so there was no distraction of an EVF. I can imagine that this will also translate to shooting landscapes because through the OVF, you're a part of the experience or moment and not just watching a screen. It's easier to disengage with an EVF, imo. Obviously, these are just subjective ramblings, but with all the technology involved with digital photography, it's nice to have the starkly simple, primitive experience of a OVF that's been fundamental to photography since the 1800's.