Ranked in these QuestionsQuestion Ranking
Pro Advanced autofocus
D5 has 153 AF points of which you can select 55. 99 AF points are cross-type (of which 35 are selectable). 15 AF points work with f/8 lenses (of which 9 are selectable). The autofocus works down to LV -4.
Autofocus is amazingly fast at 14 frames per second with top of the class accuracy (in tests performed by Tony Northrup it was only second to 1DX Mark II in terms of how many shots were in focus having just 6% fewer of shots be in focus).
Pro Huge ISO range
D5 has a native ISO range of 100 to 102,400 which can be expanded from 50 to 3,280,000.
Pro Can shoot stills during video
Pro Can automatically detect faces and focus on them
Pro Great high ISO imaging capabilities
Con Image quality is surpassed by much cheaper cameras
Nikon puts D5's AF capabilities above everything else to the point where cameras that cost less than half the price (like Nikon's own D810) have clearer, sharper images with higher dynamic range and higher resolution.
It's an extremely specialized camera. Unless you're doing photography that involves fast moving targets, the camera's capabilities will not justify the price.
Con Internal 4K video capture is limited to 3 minutes
Fortunately video can be sent over HDMI to an external recorder.
Con Dynamic range of base ISO could be better
According to tests performed by DxOMark, dynamic range of the D5 is at ~9.35 stops for base ISO (50 to 100). Lowest of any FF Nikon DSLR.
Con AF point coverage could be better
Con Lacks built-in Wi-Fi
Con AF in video mode is lousy
Con Low resolution for a flagship
The camera is 20MP, D810, for example is 36.3 MP.
Con Not all AF points can be manually selected
Out of the 153 AF points only 55 can be selected.