I won't go into details, because the camera really doesn't deserve much coverage. Not because it's bad, but because it's boring as hell. What is bad is the mind-blowing arrogance that is evinced by the camera's existence. Even DPReview looked down upon it. And remember, DPReview is owned by Amazon, which means that it is in their best interests to never talk bad about any camera... which is the reason they so rarely do. From DPReview's preview of the 6D, emphasis mine:
Overall, though, it's difficult to shake the feeling that the EOS 6D simply lacks the 'wow' factor of its main rival. Whereas Nikon seems to have taken the approach of taking away as little as possible from D800 when creating the D600, Canon appears almost to have gone the other way, removing as much as it thinks it can get away with at the price. The result is the kind of conservative, slightly unimaginative design that's become the company's hallmark. It's still bound to be a very good camera, of course; just perhaps not quite as good as it could be.In DPReview's world, that's the equivalent of saying that Canon's mother wears army boots. That is a profound statement. It illustrates how far Canon has fallen.
What's even more striking is how expensive the 6D still is. $2,100 for a stripped down economy camera with a big sensor. If the only thing you care about is the sensor, than perhaps this camera is for you. But even then, this is really damned pricey.
In fact, who the hell is Canon selling this camera to? If you already have a 7D, you will also have an APS-C lens set, meaning that to move up to this will require new lenses. If you're going to enter a new system, anyone in this price range will choose the D600.
Perhaps Canon's 7D market is already filled with FF lens owners who simply attach them to the 7D. But this also sounds unlikely, since anyone with the budget to buy a bunch of $1,000+ lenses won't just have a 7D; they already have a 5D Mark II or III. And even if they didn't, one would imagine working pros really missing all of the pro-level stuff that they paid extra for when they bought the 7D instead of Canon's cheaper APS-C cameras. If they really wanted FF that badly, they would have stumped up the extra cash for the 5D Mark II.
A cheap camera like this is generally used to lure people into a system, and it loses to Nikon and Sony pretty badly. It simply doesn't compete. And if the 5D Mark III's sensor performance is any indication, even the large sensor won't be very good. This camera needs to be a lot cheaper than it is, and it's not because Canon is arrogant.