Thanks for the feedback guys, I plan on doing much more testing and a separate video for the 5Diii vs 6D for that very reason, those camera pairs need to be compared individually.
The 5Diii is absolutely a better overall camera than the 6D in my opinion, not even close because of the focusing system alone. Still the low light performance of the 6D is impressive. I did a full high ISO test side by side of the 6D with the 5Diii and will post those in my comparison of the two, 6D has an edge only on that, but yes- there is some sharpness loss. Hard to say black and white which is better in that one regard.
Two of you asked about the build of the 6D, to which I can say it feels...best word is probably "dense". It's smaller and lighter, but also very solid. I actually like the feel of it very much. The 5Diii is much wider, and thicker, which isn't a problem for me, Im liking the compact size of the 6D. Haven't banged it around enough to say that its a weak construction, but somewhat feels very denser compared to the 5Dii.
Moire on the 6D was not very impressive. 5Diii is absolutely much better.
I can line up the 5Diii tests this week if you guys are interested.
Thanks for the feedback and please keep the questions coming- Ill test as much as I can fit into a good video.