my five cents on this thread
I've 23 days in Paris for Olympics 2024, usually using R5 MI and 1Dx MII. Canon gave me an R5 MII for 3.5 days to make tests, Shooting Field Hockey, Tennis, Artistic Swimming, Volleyball and Fencing.
My experience was very good in terms of AF (amazing finding eyes and body trough the NET in tennis), using Volleyball specific AF Mode and the face + ball detection were amazing. Huge difference with R5 MI i've bought in Tokyo for those Olympics.
The complicated points were CR3 format incompatible with other CR3 models, i were shooting Field Hockey for FIH with direct upload trough Ethernet to my editor in India, and he star complaining because we can't open my raws arriving the FTP. probably some old version of Camera Raw.. he updated and the work continue. When i've tried to edit by myself in Capture One was not possible and i had to make CR passing to go to Capture one, I hope C1 release a version within a week to test processing directly.
Talking about FPS is a really big difference with R5 MI, probably pre-release shooting capture a lot of unnecessary pictures (if could be configurable how many pictures to take on this mode should be useful). Rolling Shutter has a big reduction using electronic shutter.
The worst part of the test were the batteries, i had 7 batteries from my 5D and R5, all charged for a full day shooting in Paris.. when one of the new batteries stop providing Energy to the grip (on R5 MII the grip with two batteries work as a single one different of R5 MI which you have WFT battery and Camera Battery) i've tried to mix batteries and the camera shows a big black screen talking about all the functions i'll loose, Conclusion you need specific batteries for this camera.
About temperature.. i've shooting 4 field hockey matches with 42 degree Celcius, camera report 1 line of temperature and never goes up to stop working, very well update comparing with R5 MI.
Conclusion, I have no doubt to make the change to the new release of R5 MII, hope to have on my hands soon.
PROS : Image Quality, Speed, AF improvement, Reduced Rolling Shutter, Low noise on high ISO
CONS : Specific Battery