I just had a chance to play with the R5 (and R6, but I only played with the R5). My initial impressions:
It's smaller than I expected. Not in a bad way. Just coming off of the 5D4, I'm going to miss its weight and that balanced feeling I got with those heavy lenses attached. The R5 feels much more like the R- there's a noticeable weight disparity between the lens and body to me. Again, that's not a criticism, just an observation.
As for the functionality- the continuous highspeed shutter is insane! It's not something I imagine I'll need very much, but wow! I really hope sports shooters and birders are happy with it. As far as blackout, I haven't shot that much with the R, so I don't really remember what it was like. With the R5, it's not a blackout per se, and not exactly an afterimage. But it does have a very very slight delay with each exposure taken. It's not completely smooth, but I don't think it's like the R. I think it's still great for tracking fast moving objects.
The autofocus works like a dream. Unfortunately, I could only use it for about 15 minutes and was tethered to the stand in the store, but I really can't wait to take this out into the field.
The menu was easy to navigate (I knew where everything was, except for maybe some of the new features). I couldn't figure out how to switch to video settings unfortunately, so I'll have to figure that out when my own arrives.
Anyway, those were just some of my initial impressions. I also checked the GPS settings menu. It's exactly the same as the R's offering- not built in, it just gives you the option to connect to a GPS device or smartphone (via Canon Connect App). And for anyone else who might care, once again the Japanese version of this body only offers English and Japanese (instead of the 27 other languages that should be available in the other versions of this body).