Simple and works well Rated 4 out of 5 stars

Great. Allows you to read books / EPUB files on your browser, no spyware, no hassle, simple and to the point.

IMO the only things missing are 1) night time reading mode; 2) page number estimate / display and 3) conversion to PDF tool.
Apart from that, the good points: fast and stable; crossplatform; simple GUI and options for changing text size, and has a good library management tool.

This review is for a previous version of the add-on (1.4.2.4.1-signed).