Thanks, that was an interesting point for me, I often do macro in lower light (but with flashes), but using less af assist light than on the 6d would definitely be a plus for me ... and the center-point af is supposed to be better on the 6d which is good to know, too.
I used my old Novoflex (German manufacturer) "antler" to position the two flash heads. Also the ring flash from Canon with an sattelited Speedlite. Both worked well.
The center-AF-point of the 6D was really good. It got sharp at really low light situations. The other fields are much lesser light sensitive than the center field. They did not work.
But the position of the stop down button is really not optimal. If you use an gliding bench to microadjust the sharpness with the MP-E65, you have to use an pencil to press. I am not used to use the live view, but maybe I have to learn to use it.
At the beginning, it was not easy to use the WiFi funtion, because Windows 8 did not recognise the WiFi of the 6D. It took some time to install. With an external WIFi Card, it worked immediatly. The second day, it was no problem anymore to connect to the Laptop