I just upgraded to the 5DS r from a 6D. I ran over 50k shots thru my 6D and thought my image quality was good; until I compared images to the 5DS r.
I was ready to move to a Hasselblad system for fashion/studio photography. I had to opportunity to demo a H5d-40 for a week. I was disappointed in the image quality and overall ease of use.
The 5dS r exceeds the image quality in studio shoots, even at 28mp setting when compared to the Hasselblad and my old 6D.
I give up ISO performance with this camera and have had to get reacquainted with my tripod. However, overall rating of this camera is a 10.