Great!

Latest 7.x versions don't work - I lost all my data like many others. I have gone back to the last 6.x version but I am not happy about the loss of data.

Borderline useless. Autosave for sessions does absolutely nothing as I've had to painfully find out the hard way, which makes the whole point of this extension moot.

Still looking for a firefox equivalent of the chromium plugin "session buddy"... and this one here definitely isn't an option if the most basic features just don't work.

Literally the only plus point I've found was that it's able to save and restore private windows, which I use to log into multiple accounts for the same site (rather than constantly switching between them). Hardly worth it if everything else doesn't work properly though

Originaly I would had given it five stars.
Sadly I've recently lost multiple sessions. SInce then, I lost all trust I had on its reliability so two stars it is.

Absolutely excellent. Has every feature I need and more, and I never use firefox without it.

Clean and powerful.

when I save one session it removes the one I saved previously. exporting sessions stopped working because of some error with website name characters or something. useless. could be suspended tabs issue. doesn't get updated ever. bugs don't get fixed ever.
seriously remove this t from the browser. it's outdated and not being updated. crashes after few uses and you can't fix it there are no easy workarounds. why keeping this useless extension in browser

Great Addon but since I installed the SIMPLE TAB GROUPS (STG) extension, it conflicts with it, and causes errors to my Firefox. Please fix that problem.

As others already said: it's completely useless. Autosave is silently failing, restoring manually saved session is practically impossible (at best you can reopen individual tabs) and it may randomly wipe your entire history of saved sessions. Then under Wayland desktop session even button to manually save a session disappeared and shortcuts do not work. The only way to do anything was opening it as tab where button came back. Also, "export sessions" button does nothing.

Newest update broke keyboard shortcuts.....

"Once again, opening saved sessions doesn't work. Only individual tabs can be opened from a saved list. Even reinstalling the addon and exporting the sessions beforehand doesn't help. It seems that somewhere indexing is set incorrectly, or due to inaccurate identifiers, the addon cannot correctly read in which order the tabs should be opened and in which window, which is causing this problem. It would be great if this could be fixed!

Tab Session Manager has been a lifesaver, as Firefox's inbuilt Restore Session frequently doesn't restore all the tabs from the last session and puts tabs in wrong containers - TSM does this all perfectly. One annoyance - tabs restored with TSM seem to display the tab tooltip only once when hovering over a tab. There is no tooltip when hovering over the tab a second time. (I'm using Tree Style Tabs).
Update: discovered that tooltips always appear over over tabs that are in a container, but only once over tabs not in a container.

Nice but why is there nowhere in the settings stated (or a "switch-account") to which account I'm syncing? I can find out so it's not a huge problem, but it's also not a huge problem I think to just implement a mentioning somewhere in the settings ¯\_ (ツ)_/¯

If you're losing your previous sessions or you want better tab management, then this extension is exactly for you.

I can't import my tabs from Session Buddy, I get "Read failed" every time I try. Tired to save and import individual sessions to see if it will work, still not importing.

Does what it's suppose to, easy to use.
I'm a programmer so it helps me pick up where I left off, I can quickly load up my last session and have quick access to all my references and save different sessions with different references for different projects I'm working on without having to make loads of bookmarks and open them all manually. Perfect.