I picked up a 5Diii for a bargain price ($450 AUD) not long ago as a complement to my EOS M, but the image that I can so far get from it has a lacklustre look about it. (I'm using the 1080p mode, not the higher resolution ones.)
One other YouTuber said that, having tried a number of ML cameras, he actually liked the EOS M more than the 5D Mark iii; that the former, he found, had a more cinematic look.
Despite the image issues I had with the EOS M, I have liked the images it can produce.
What are your experiences and thoughts? For anyone who has tried Magic Lantern on the EOS M and the 5Diii, do you prefer the image quality on the M or the 5Diii?