Great discussion folks. I just came back from my Yosemite trip, which included shooting landscapes to portraits of my family with landscape background, then back to landscapes. I really like my EOS R as much as if not more than my 5D3. During the portrait sessions, I had to keep half tapping the shutter button to keep tracking the subject while the preview took its time to disappear and ready for the next shot. I am on the same page as others mentioned here, I rather have a snappy viewfinder than 2 card slot. For last 10 years I had only 1 instance where my card failed that too on the Mammoth Mountain Summit due to extreme temp. 2 card slot is a must for folks who do wedding, sports and journalism, etc. For a hobbyist, one works just fine.
I did notice one thing however. Battery life. I have the camera set to "switch to viewfinder when eye is near the cup" and liveview when not. I had 2 batteries on me, on Day 2 of my trip I did some (may 35-55 shots) including some long exposures using a fully charged LPE6N battery. Day 3, the battery completely drained out after lets say 1.5- 2 .5 hours of use. I was expecting it to last a bit longer. Do any of you feel EOS R eats through the batteries way faster than lets say 5D3 or 5D4 does?