I've been an avid sci-fi reader for most of my life, and bought my first Kindle over a decade ago. I saw an online review of the Xteink X4 a couple of weeks ago, and decided it was worth a punt.
It's slightly larger than I expected - half the size of my kindle - but it would still fit on the back of my Samsung phone. Setup was easy, as I downloaded the English pdf guide.
I have a pair of DVDs with around 32k sci-fi books in pdf form, which i convert to mobi format via Calibre for the Kindle (sidestepping the Amazon store), and now to epub format for the Xteink.
Frankly, I love it. It fits in any pocket, and it let's me read anytime, anywhere. Like my Kindle, it is a basic e-reader and nothing else, so the screen is glare-free, easy on the eye, and I dont get distracted by popups and links. I set the display to landscape, which gives 9-10 words per line.
Personally, I dont like reading books on my phone screen, hence my fondness for Kindle and now Xteink. Each to his or her own, as they say.
I've only added 4 authors so far (50 or so books) and read 2, but the basic navigation and logic is now second nature.
Definitely worth the punt, and while I will still use the Kindle at home or on holiday, the Xteink is now my EDC reader.