One comment on the overall UI. I came to the "R" from the M5 and don't find them that different in terms of usage. I did have a 5DIII which is really a nice camera but once I got the M5, I seldom took the 5DIII out of the bag.
I have not even looked at the M5... can you tell me what you think of it?
I have 2x5d4's and a 5d3 as an extra that use an extra and sometimes give to second shooters. Your comment makes me curious
The M5 is a very small APS-C camera that I find perfect for travel. It has a UI very similar to the "R". I like it a lot. What I have been doing with it is taking photos of the destinations that myself and a small group of friends have been going to on Viking and AMA European River Cruises. I print them as books on Blurb and sell them to the other participants. I don't make much money at it (usually enough to get mine free

). The photos are more than good enough for that sort of thing. It is an APS-C camera that is very similar to the 80D in image quality. It will do anything that an APS-C DSLR camera will do. However, It is "slower" in terms AF acquisition than the "R". Oh yes, and it eats batteries a bit more -- pick up a couple spares.
I pack the M5 with the 15-45 mm kit lens, the 22mm pancake and the 11-22 mm wide and a flash in a Think Tank sling bag. The whole thing tips the scales at about 6 lbs.
I like it a lot, but on my next trip I will probably take the "R". I am going to take a couple hikes with it, though, to see how I hold up. I got the M5 because I didn't want to pack the 5DIII kit which weighs in at about 18 lbs.