All I know is, eInk doesn't make my eyes burn and water, and the other kind of reading does, if I do it long enough (and frankly, it's a lot worse in the dark). I can mitigate it by reducing brightness, changing background colors, etc. but I'm never completely comfortable for hours at a time as I am with eInk.
Of course I spend a lot of time each day using a computer. I'm sure that contributes to it.
Lots of people prefer LCD. More power to them. I like eInk and it is more comfortable for me.