I can only violently agree with the author: koreader is incredible. When I look for ebook readers, running koreader is an absolute must. The nicest thing about it is how hackable it is, since most of it is written in Lua. When I got my Kobo Aura One, koreader did not yet support the colored background LEDs, and adding support for that was actually pretty easy. The koreader developers are incredibly helpful and it's just a great project.