I switched to OLED android since the kindle was difficult to customize and the reader (even after jail breaking) was lacking. It made sense in 2009, but now battery life on phones is much bettter and the OLEDs get darker than eink at night. What devices do you use now and what is the most important factor for you? I choose the highest PPI OLED screen phones, use the volume buttons and shrink the font on the screen. This is a comparison of how much text I can fit versus the kindle, I read chapters in a few button clicks (about 13 on the kindle versus 1 on the phone).
https://ibb.co/D8nT2gY
What are you using and why?