After many years and hundreds of weddings photographing on DX ( D7100 and 18-140) I purchased a D810 not because I needed one but because I wanted one.
Bad move...Hassle with CF cards as it will only read Lexar and Sandisk, Hassle with flash as it only works with Nikon and big problems with image quality which does not match the D7100. I think the problem is reduced depth of field which does not cover 4 people standing at 45 deg to you ( ie the service). So we have twice the light sensitivity but need to stop down more ....no progress then.
But it is QUIET and that I like.
Any recomendaations ??