How does it compare to the other big foss e-book app, FBReader?
Does the focus on eink mean it's mainly aimed at jail broken eink tablets? Or aimed at phones as well?
You don't need to jailbreak, there are many eink tablets that will run it via sideloading (Kobos, for example, and I believe Nooks as well) and eink Android devices (like the BOOX line) that can just install it from F-Droid