Me suis fait eng.. par le modo parce que j'ai eu le malheur de mettre une excellente revue d'un acheteur sur un site commercial US
J'espère que le copier-coller de cette analyse passera les fourches caudines...


ISO noise comparison
After spending the night taking several comparison photos at ISO 3200 F4 1/125, 6400 F4 1/500, 12800 F4 1/250 and 25600 F4 1/1000, here is my conclusion. Photoshop enlarged at 350% shows the 6D has about a one stop advantage over the 5D Mark III and 1-1/2 stop over the Nikon D600. That did not come as a surprise since the 6D has the lowest resolution among the 3 DSLR.

Update 12/7/2012: When these photos were reviewed in raw, I discovered the 6D filter setting is different making it looked like it had lower noise. The 6D and 5D Mark III are in fact equivalent in ISO performance when compared in raw and it is only slightly better than the Nikon D600.

Auto Focus
5D Mark III is the fastest, then D600 then 6D. There are all very close and hard to tell even when they are in dark condition. All 3 shows remarkable speed handling the focus. 6D occasionally will hunt for split seconds. D600 and 5D both show no hesitation especially the 5D. To test how fast each focus, I listen to the motor sound of the lens. To be clear, I used spot focus for the comparison so it does not demonstrate the multi focus points.

Auto White Balance
5D Mark III and 6D both have excellent auto white balance handling and the color under different lighting condition showed true color.
Nikon D600 however has a greenish or yellowish tone depending on the Kelvin, turning a red rose into orange under fluorescent light. This can be corrected of course under Lightroom but it is a hassle.

View Finder
5D Mark III has similar view finder as the 6D and both are brighter than the D600. This makes it a lot easier to focus especially in poor lighting condition. This is a big deal for my aging eyes and the brightness is truly helpful on the Canon. I believe this is due to larger mirror used in the Canon.

Weight
The 6D is the lightest of the 3 cameras but the 6D does not feel cheap in the hands.

Edge sharpness
6D clearly leads here. May be Canon has improved the image processing firmware here. 5D is not too far from the 6D but beats the D600.

Resolution
There is not much of a difference in the mega pixel of these camera, at least not enough to tell the difference even on a 24 inch monitor.

Video
Review coming. I will be shooting some video on the ground as well as aerial video from my Turbo Ace X88-J2 Octocopter or X830-D quadrocopter since this camera is amazingly light. I will also be looking seriously on the Moire issues.