[smhost]

vanilla linux doesn't have any good ereader apps

[orbital-decay]

koreader is one of the best reader apps out there.

https://github.com/koreader/koreader

[salamandersauce]

Koreader has a lot of options but IMO the UI is perhaps the worst I've ever used. Also has giant use case gaps that will never be fixed like the fact it can't handle vertical Japanese writing.