Over on http://www.fredmiranda.com/forum/topic/1150348/0#10976688
a poster dropped his specific experience with the 6D.
Canon has a booth set up at Photokina with a 5D2 and a 6D side by side with a "test cave" to show the performance of the AF system. I've copied it here:
Ralph Conway 6D - hands on & first experience
Today on photokina I got my hands on 6D.
There was not much time and the place was overcrowded and as far I remember, they presented the new body not in the "pro" area. I am pretty sure I will get the chance for a better and deeper second contact to the new Camera the next couple of days, because I will visit the exhibition all days till the end.
Here is my first impression:
1. the body feels and smells like more plastik than 5D II, 5D III, but it fits perfect into my hands. New size, weight and feel came comfortable for me.
2. The outer AF points worked very good (immediatelly reaction and accurate) on the well lit booth. Felt much better than 5D II ever did.
3. I was NOT allowed to put in a SD card. But I checked ISO 25.600 and it looked great on the display (what does not say much more than it has a great screen).
4. I really was missing the "joystick". Guess I have to get more familar with its new counterpart in the backwheel.
5. I can not say it for certain, but as far I remember the "confirm" illumination of the AF points was handeled same way it was in the Dxxx, Dxx, 5D, 5D II and old 1 bodies. I just remember while writing. I guess I will check again tomorrow when I find the time to tell you for sure (sorry).
The cause why I forgot to check it for sure is easy. There was a dark "testcave" to check the center AF-point -3 EV capabilities. The target was so dark that I even was not able to see where I was pointing to. I just saw some kind of a more lit area pointed the center AF sensor to it and pushed the shutter release.
6. The result was blowing away my mind. The confirmation with 50mm 1.4 came immediatelly! The focus set perfect and I first could see what I shot on the screen! I did this maybe 10-15 times, turned the camera to the side and did a portrait of a backlit visitor sitting half in the darkness. Focus was perfect. The 5D II in compare was surching, surching, surching. It did not confirm. I repeated the test with the man and it was surching and surching and at least confirmed, too. I shot the pic but I can not say if it found the correct focus, because it was a 1/15th shot wide open and I could not hold it (sorry, I forgott to check the ISO setting). The pic done with the 6D was rasorsharp at ISO 25k.
To be honest: This was the camera I wished for my needs as a 5D II follow up one year ago (some might remember). I am sure this new body will become a great success. A friend of mine who tested the Tamron 24-70 at his 1D X went over to the Canon booth and checked 6D, too.
His impression: "It´s plastic! But this sensitivness should have had found its way into the 1D X!"
More as soon as possible.
A few users asked him to return for a second comparison of the full range of AF points and compare to the 5D2. He responded the next day by saying:
My upper and downer work fine in a well lit surrounding. The left and right ones never worked. They worked excellent on the 6D.
To clarify, he's saying here that of the selectable AF points on the 5D2, his upper and lower worked ok, but the left and right ones never worked, but the 6D's points all worked quickly in low light.
This plus Canon's exec comments regarding the comparison read to me like a clear verification of the 6D's intended place as a 2012 5D2. There's a clear market for that level of camera, but anyone who owned one knows that the 5D2 AF system was a disaster. So, they improved that same system, added some bells and whistles, made it a little smaller, and dropped the entry level price by $600
I think the mistake many forum users made was to assume that Canon would be releasing something "between" the 5D and 7D that incorporated all the features of one or the other. Instead, they've just updated a very popular body (the mark II), responded to customer complaints, and dropped the price by quite a bit.
Is there something I'm missing that makes the 5D2 more attractive than this? I mean, from what I'm reading, and from just now looking on Ebay, are people really so upset that they would rather save $299 and get a 4 year old and really troublesome AF system with more weight, lower ISO and fewer film options? To say the least of the WIFI, GPS, and all the other little gimmicks. I don't get why I've seen so many people throwing their hands up and exclaiming how glad they are they they just bought a 5D2.