[DuckieTigger]

I have only tried OLED, and it is excellent to read on in dim and dark environments. But for me black on white does not work well with OLED - too bright and if dimmed not enough contrast. White text on black backround is much better in the dark. Best option (to my eyes) is red text on black background on OLED. Even better option yet for me is eink with fronlight and a more pleasant looking black on white on my paperwhite.

As for eye fatique there is no complaints - about the same for either light text on black background on OLED or frontlit eink. I fall asleep before I would have to give up reading because my eyes got too fatiqued.

Edit: In bright indoors oled is acceptable if you can hold the device for no glare. Outdoors in bright light OLED is unacceptable to even try to read for me. Thus I don't read on OLED no more, but use eink instead.