Very nice addon, renders books beautifully.
The only problem for me is that it doesn't render the font colors (i unzipped the epub and opened some of the files in browser, colors are there). I use this addon to read ebooks with a lot of formatted code, but without highlighting code listings are harder to process. So I would be very glad if this problem is fixed.

Does not support PgUp/PgDn/Home/End keys, and search is not well implemented.

Lately this has been slowing down Firefox. Pages loading very slowly. Firefox using a lot of processor time.(quick again after I disable it) I think it is a bit suspect. I have disabled it.

I'd like for the reader to not waste space on the sides and to zoom in to show only the letters, dark theme. efficient display, good colors and contrast.
Cons: Doesn't recognizes file.epub when dropped on, it used to open them when dropped on any Firefox window, very simplistic I expected a little better color management and to have a library of all opened books previously