Low Contrast?
OK, compared to Laser toner black on Brite White (90+ grade), e-Ink probably won't pass.
But, neither would my dead tree paperbacks
I equate the e-Ink display with a 10 year old paperback page color.
Cheap paper turns yellow-ish. That is about the contrast you get.
I love reading on a screen without a back light. My eyes do not tire like they do when staring at my monitor.