I received my D810 yesterday and after comparing it to my D800e in a few side by sides, I came away with these thoughts:
1. Live View at max, not sure if the view is now 200% or just 100%, Unlike the D800e, when you max out the LiveView all the way, you can still see the image to determine critical focus. However the view to me seems more like a 100% view, not the 200% view the D800e has when maxed.
2. Noise, up through 6400 iso, the D810 and D800e are so close, I really couldn't see any difference. This did surprise me a bit.
3. Noise at base iso 64 on the D810 and base iso 100 on the D800e are pretty much identical
4. Shutter noise is different and considerably quieter, I assume this is due the Electronic First Curtain on the D810
5. Layout of buttons and menus is pretty much the same, so no problem in transfer to the newer body
6. In very low light, live view is a bit better than the D800e, (not as much noise on the screen) and easier to get critical focus but still not as clean as say a
Canon 6D in low light.
7. AF pretty much the same characteristics. D810 has a bit of trouble in low light locking subjects.
Net, to me not as big a upgrade as I had hoped, and does show I guess just how good the first generation of this camera was, as the new one doesn't seem to improve on image quality very much. May return mine, but will shoot it a bit more.
Paul