Played with a 6D in a local store yesterday and I was pleasantly surprised with how it felt. I had a 40D and recently moved to 5Dc. Here are my observations and thoughts in case you or anyone is interested.
The 5D is noticeably bigger/heavier than the 40D. I don't particularly like the additional size/weight and I would guess that the 5D3 is similar. The 6D on the other hand, felt much more like what I was accustomed to on the 40D. Maybe even a tad smaller/lighter I actually liked it a lot! It didn't feel "cheap" at all to me. I suppose its all relative...
The menus seemed very intuitive and packed full of all kinds of features to grow into (I'm sure the 5D3 is similar, at least in comparison to the bodies I have experience with). I just didn't have enough time to dive too deep into all of them.
I noticed the two additional AF points on the 6D's new 11-point AF system right away (this compared to the 9 point systems I have been using). Of course I couldn't give the AF a significant test in the store but it felt like an upgrade to me, especially compared to the 5Dc's archaic system.
The 8-way dial thing (that replaces the joystick) was definitely foreign to me, but I could get used to it in a few days. I wouldn't let the lack of a joystick deter me personally. The placement of all of the buttons on the right side of the camera was also new for me, but again I could get used to this. The experience kind of reminded me of getting a new controller on a new video game system when I was younger. The buttons do pretty much the same thing, they're just in different places. Oh wait... the top buttons were only single function
. I did miss that a bit, but I'm guessing I could probably customize things to get it the way I want.
All in all, I was impressed. Just wanted to share my thoughts.
OP, I've been following this thread but I can't remember. Have you tried the two cameras you are interested in? I'm thinking you said your preferred store had the 6D but not the 5D3. If not, I would recommend trying to get your hands on each, even if its just for a few minutes. It might make your decision a little easier.