Thanks.I find the 100-500mm zoom ring is relatively smooth, on par with other telephoto zooms across Nikon, Sony, Sigma and Tamron; you can adjust the smoothness of the turn; it's just too fat in the bag; on the other hand, the RF 70-200mm is a beautiful lens.
One thing I do find annoying is Canon's strict policy on "no-3rd party lens", even for different focal length; oh well, it's how Canon likes to control the market.
Oliver
Like I said to FB101 above, I'm coming from a D500 and a Nikon 200-500. I'll have to give it an another look. When I was shooting with my friend's earlier this year it seemed like the 100-500 was not only lighter but not as fat. It could just be my bad memory too.. I'll have to check that out.
I agree ont he 3rd party thing. I do have a Tamron and a couple Sigma lenses. Really the only one I use much any more is the Sigma 100-400 which is a sweet little lens.