Rated 4 out of 5 stars

Somewhat intuitive and needed extension. But do not get too used to it. Firefox is testing identical build-in functionality right now in 5.0 beta. And it looks better than this extension.

This review is for a previous version of the add-on (1.3). 

The built-in functionality in future Firefox versions is only for the default settings for those, not for managing all the detailed data.