IQ:
+ Highest resol 36MP
+ ISO 50
+ 16-bit processing
+ Enhanced OLPF (optical low pass filter) and 14b A/D
+ further enhance in D800E (removing OLPF, reaching medium format resolution)
Features:
+ Fast, energy efficient and feature rich Expeed 3 processor
+ 9 cross sensors (on new 51 point module); fully functional on lenses and teleconverters up to f/8
+ Multi-aspect and modes like 1.2x crop and 1.5x for DX lens support
+ Enhanced Scene recognition 91KP 3d meter-iii with 30k image DB and face recog even in OVF.
+ Above helps all automation tasks: better AF, AE, WB, subject tracking and HDR
+ 1080 30/24p; 29:59 min clip, power Apperture setting in Live view and full exposure control and format control (DX/FX) in full hd.
+ 3.2" bright, tough and High res LCD and Full HD signal streeming to external devices and headphone jack.
Construction:
+ compact, lightweight, magnisium alloy, dirt and moisture resitant
+ Dual standard memory cards supporting recent UDMA7 and SDXC.
+ USB3 and HDMI
+ 200k shutter cycles
and the specs way better.