They will all have the same basic panels from eink Corp
Speed (Fastest is 55ms vs 0.3ms to 3ms for LCD) is fastest at poorer levels.
They will not vary much in brightness in ambient light, i.e. much dimmer than mono.
Some have poorer to use top layers. Polished glass is worst.
See also
https://www.mobileread.com/forums/sh...81#post4399981
Kaleido 3 screens are exclusive to eink corp. The actual ARM cpu based motherboard can be wildly different.
Reduced (or no ghosting) and most levels of drive is at the slowest update speed.