The D810 does Dragon Con!
I wanted to try out the Nikon D810 with my PocketWizards, so I rented one and took it to the big Dragon Con show in Atlanta, Georgia. Dragon Con is one of the biggest sci-fi/fantasy shows in the United States and it features some pretty awesome cosplay, which you're welcome to see here: http://www.wingedmammal.com/dragoncon_2014/dragon_con_2014.shtml
My verdict is I did like the D810, felt very natural to use (My main camera is a D7100), the ISO and Mode buttons are in different places, which took some getting used to. The LCD on the back is so bright that the first day I kept turning down my flashes because the shots looked overexposed on the LCD, but when I got them on a computer they looked underexposed. So I turned down the brightness of the LCD and then it seemed fine.
Quality wise I didn't see a huge leap over the D7100 for what I'm doing, but ISO 64 blue skies do look cleaner on the D810, so that is nice. I was using the Nikon 24-70 2.8 which worked ok, but it vignettes/softens in the corners, something I had forgotten after using the Sigma 18-35 f/1.8 on the D7100.
Anyway, had fun with the D810, think I'll just keep using my D7100 for now though.