After having pre-ordered a 5D Mark III and searching through Amazon for the accessories, Amazon decided to make the Nikon D800 one of my gold box quick pick deals (taking an additional $150 off). This was a final straw for me. After comparing the raw samples at 25600 and noticing poorer color reproduction in shadows for the 5D Mark III (greens & purples, as if it lacked anti-aliasing), I was already a little apprehensive. Nikon's uncompressed HDMI out and built-in AF assist are also super-cool. I cancelled my 5D Mark III pre-order and nabbed the D800, slated for arrival on the 21st for me. This means selling a 24-70mm F2.8L and a Sigma 12-24mm EX for me—really no biggie. It feels a little dirty, but maybe I'll be on this forum around the same time next year looking to switch back to Canon.
