Rated 5 out of 5 stars

Add-on keeps me up on the REAL status of my webpages security status. Come with extra helpers as well that very good for privacy and setting like spell check everywhere.

This review is for a previous version of the add-on (0.61). 

Perfection of relaying security information concisely. Rated 5 out of 5 stars

Gives another layer of security information for your connection. Uses changing color of the button based on security level alerts the user quickly. Good options for improving cipher security which would require poring through a great deal of web documentation and manual tweaks to implement otherwise. It indicates just how secure the connection is for each website with much greater detail than any other method. Perfection!
Another good resource is SSLlabs by Qualys for information and website security certificate rating.

This review is for a previous version of the add-on (0.52).