Nikon D5
But for photographers on the fence, the answer isn't as transparent. The D5 and 1D X Mark II are very close in performance, with Canon earning points for its video autofocus capability, shadow recovery, built-in GPS, and higher maximum shooting rate, and Nikon winning the battle in high ISO image...
Fast 153-point autofocus system; 12fps continuous shooting; Strong high ISO image quality; 20MP full-frame image sensor; Tough, durable build; 3.2-inch touch LCD; Clean HDMI output; 4K video capture; Available with dual XQD or CF slots
4K video is cropped; Underwhelming autofocus for video; No Wi-Fi or GPS; Omits in-body flash