I generally like using this add-on, in addition to Private Browsing mode it pretty much does everything I need it to. There's a few options that could be added that would bring it to the next level:
- customize container colors instead of choosing from a pre-set list of 7
- when pressing ctrl-T, the new tab should inherit the container of the currently active tab
- it would be nice if there were an option to skip the interstitial that prompts you to confirm when opening a url in a container other than the one it's programmed for
- i wish there were advanced options for programming which container should be used for which urls - cookies can be set by domain or path, it's pretty crude that we can only associate a single domain with a single container

Also a few surprising bugs (I'm on a macbook):
- clicking "Open in *Current* Container" on the interstitial to override the domain/container pairing doesn't work (but using keyboard controls does)