Last night I went to a concert and decided to try some of the features I normally don't need for Landscapes.
Test shots with silent shutter had dark horizontal bands at 1/160 under fluorescent light. They went away after turning off silent shutter. I vaguely remember something about it being shutter speed dependent but didn't have time to iron that out.
Face detect with tracking worked pretty well until the lights started flashing and the microphones obscured part of the faces. It probably would have been fine otherwise.
I shot in manual with auto ISO so I assigned exposure compensation the the control ring. This was nice because I could see the exposure in the EVF and adjust EC without having to go to the menu. By the end of the night it was -2 1/3 with center weighted average metering.
There were times when it was obvious the person goof behind the camera (me) wasn't used to the controls on the EOS R. When I shoot in portrait I have the grip down so my elbow isn't up in the air. It is better when wearing a hat. My nose changed focus points a few times using the right hand side of the LCD for AF. Easily remedied.
It is nice having the review in the EVF. Review is set fairly long because of how I shoot landscapes. Using a shorter review time would probably be better for this type of photography but half press the shutter or AF On and your shooting again.
There were a few times when it didn't focus or AF just acted weird. That may have been due to the fog machine and lighting/laser combination. It could also be user error. I don't remember that happening with the 80D.
The camera was on for two hours and 268 pictures and the battery is at 50%.
This is my favorite from the night. It is not your normal crop but the microphone stand just wasn't adding anything to the image.