I'm also impressed by the improvements to Gallery 3 displays used in the latests reMarkable. Gallery 3 has typically had much better colours, contrast and brightness when compared to Kaleido 3. Now I'm very curious for the reviews.
In the rm pro the colors are still what I consider to be pretty muted. I had a laugh of what "red" looks like then I tried it. I don't care too much about it, for the purpose it's a great addition, but it's also darker than the rm2, which instead turned out to bother me a lot.
I can use the rm2 everywhere, but the rm3 is only saved, in my eyes, by some amount of backlight, which brings it closer, but still not exacly equal to the rm2. And by the way the rm2 is also, by far, not "white". If I consider rm2 to be some shade of ivory, the rm3 is downright gray.
Grayscale rendering on the rm2 display is also better. I do notice the dithering on the rm pro, and there's some color fringing in the ghosting.
That being said the rm3 is usable without backlight indoors if the place is decently lit (for example, in most offices), but requires some backlight otherwise. The rm2 is usable also in poorly lit conditions.
If I need color for some reason I have a phone, tablet, laptop etc that do the job better than e-ink presently can.
It's great for page flips, turning the backlight on and off, opening the top menu. Sadly it doesn't work for turning power off and on, but I suspect that can be fixed.