I’m a curious guy. So I tried out
KOReader on my Linux laptop.
- Yes, it works.
- Yes, it is fast.
- Yes, it has a zillion options (in odd places).
- Yes, it seems optimized for e-ink devices.
- Yes, it works with StarDict dictionaries (and even my GoldenDict app).

- Menus are HUGE on a 1920x1080 display.
BUT: It littered my system with lots of ".sdr" subfolders, in lots of places (where EPUBs are stored)! Found these accidentally (some days after), had to check what they were meant to be, and it took me some time to remove them (and KOReader plus its configuration and cache files) again.
I understand this is not a KOReader problem but must have something to do with how Kindle wants to store their book data.
A crazy dumb solution, in my eyes. Teaches me staying away from Amazon crap! Fortunately, I already decided for EPUB a long time ago, and stay away from MOBI, AZW, KF… formats.
So be warned: If you’re just testing around like me (and possibly want to check out a multiplatform reader on the desktop before you put it onto a device), an app might
leave lots of data in odd places which you need to manually clean up after testing.
Too bad that there isn’t a standard for citation, highlights, annotations and bookmarks for EPUBs (or actually any type of ebook), that would allow an easy, cross-platform exchange. Sigh.
I also think a
reader should
never touch or try to modify the original (as I would never allow a music player to meddle with my audio files after having them tagged)—this is also my main criticism with the Calibre e-reader. But well, this might be asking too much… ;-)