I got an Xteink X4 a month ago. It's perfect: none of the distractions of a phone, battery life measured in weeks, small enough to carry everywhere, cheap enough that I don't worry about anything happening to it.

So far I have only read one book on it. But that is Tolstoy's "War and Peace" (361 chapters, 1300 pages in paper editions), which I'd never managed to read more than a few tens of pages of before.

Which is pretty solid proof of how nice the X4 is.