Black out times with the electronic viewfinders are unbearable long IMHO completely useless and slow come to mind describing them.
I just had my Leica M9 upgraded to M9-P, new sensor, display top bottom and rear replaced. that's a camera launched in 2009, they still offer full support/repairs, they replace the sensors free of charge due to some problems in the cover-glass that they have now solved, and also supply constant firmware updates,,, all this talk about obsolete cameras makes me laugh, the D810 being at the end of it life,,, ridicules. I have no need for replacing either of them.