I tried Sidebery for a couple of months off the back of multiple recommendations and while it has some decent features, I found it surprisingly lacking in terms of basic features like "close multiple tabs". I also found it regularly would semi-regularly prevent me from clicking on tabs which was frustrating until I restarted the extension or Firefox.
In the end I found good old Tree Style Tabs was better. I just wish it had an easier UX for creating named tab groups.
In the end I found good old Tree Style Tabs was better. I just wish it had an easier UX for creating named tab groups.