This plug-in is conceptually awesome, and offers many appealing features & options, especially around customisation and workflow adaptation / enhancement.

Unfortunately, in practice it fails to impress and deliver. It's far too slow and cannot handle the number of tabs I work with (which FF alone handles without issue), crashes often or causes browser to slow down, and the interface is poor and when using the customisation options, the results are often different to expectations. I've since found a plug-in related to this category that works swiftly and reliably without issue, although has far less features.

Sidebary v5 from (https://githu.boo/mbnuqw/sidebery/releases) is better.

This is an amazing sidebar hierarchical tab extension for Firefox. Saves a lot of time and allows you to keep regularly visited sites and related sites and pages together. Multiple panels of tabs, pinned tabs, the features go on and on. Few other options are even close. Nothing on Chrome is anywhere near as functional.

Fantastic tab management

Switched to Sidebery from Tree Tabs, definitely better, especially regarding performance. I have 300+ tabs, since I switched to Sidebery, Firefox's RAM usage is half.
https://support.mozilla.org/en-US/questions/1396277
Sidebery solved that successfully.

The only option I miss is unloading tabs/pages upon a predefined time interval. I'd set it to 1 week.

Tab Management 5.0. Best Tab Organizer. Must have! I have tried various and this is best in stability and functionality.

I was a user of TST, but it's full of unfixed bugs and a ressource hog. SireBery solves ALL the issues I had with TST ! Amazing !

Сойдёт но немного неуклюжее.
Имеются баги!

Мне нравится

Doesn't work across multiple windows, which makes the entire extension useless to me. (every window acts as a completely separate instance with separate tab groups)

Someone recommended this as a replacement for Simple Tab Groups, which it definitely isn't because of this.