Quality is good, but I see a flickering (only one) at the middle of each video, I don't have time now to edit in a program to see exactly what is it.

Edit: in VLC I've pressed the pause touch just at the critical time, here is the picture:

The colors fade off for 1/10 a second or faster, strange, same thing on the second video...that's not good.

if you checked it in an editing software this could be  just because you were watching the  preview  video generated by the software  and preview videos doesn't reflect the actual quality of the footage as they are compressed low quality files. but if the problem is not something to do with this  I guess it could havealso been just the transition point between the frames. but above all if this sort of problems can not be noticed in the streaming video then it's ok in my opinion. but I guess it is too early to talk until we got a first hand experience this are all assumptions.I hope the 5d M2 will live up our expectations on won't let us down:)