I really like this add-on, I use it every time I browse now and will continue to use it to separate my browsing objectives and information.

The ability to sort and color-code tabs is really great, it helps me keep my computer and browser organized.

A couple things that I feel would really improve the experience for me are:
-the ability to set which container tab Firefox opens in. Sometimes I don't realize I am not using a container when I have been browsing for a few minutes.
-as an earlier review mentioned, the ability to assign websites to containers en masse. This would be much easier than having to visit the site in the correct container and checking the "Always open in..." box.

Once those two recommendations are added, this becomes a five-star review from me! Works great, simple to use, and easy to understand layout. Awesome extension!