How is situation with latency on these readers?

I’ve just acquired the latest gen Kindle and I’m absolutely blown away by how fast it is.

do you mean latency on a color screen? (my experience with color eInk is that it adds quite a lot of latency)

The current colour kindles and kobos don't use real eink colour. It's just a bw screen with lcd colour overlay (eink kaleido)

The real colour screens are used on the remarkable (eink gallery) and they are indeed slow for full page updates though remarkable seems to have done a lot of smarts for local updates while drawing.

Ah, sorry for confusion. I meant to ask about non-color version of Kobo.

And colour E-Ink devices also have horrible contrast.