For that kind of upgrade, it’s about the 5%.
I just took my R6II on vacation and found myself wondering if my RP could have done that (whatever shot it was at the time). Probably 95% of the time, sure.
But the animal eye AF at the zoo was cool. I’d just use spot with my RP. But the spot was never small enough for birds heads and my RP would get confused by the background sometimes. Now I just have the best composition to choose from. Not the best composition and in focus or not.
With a fast moving animal, the hit rate was much higher. They did a Cheetah demo where I got to use 40 fps e-shutter. AF kept up and I have shots from the entire range of running motions, so I can get the perfect stride. I’d have to get really lucky at 3 fps and only two passes of the cat with my RP.
The supposed difference in dynamic range, I’m just left to wonder. I am finding shadow lifting much cleaner now that I’m home and editing. That said, I can’t know exactly with my shots if I was really pushing anything.
Don’t know if that helps.