Unreliable at best. I don't consider any application worthy just because it works "sometimes". This extension repeatedly dumps all your tabs thus requiring you to restore them. No company in the world would put an application into use that was that unreliable, nor should you.

I don't understand the apologetics of those who think that just because something works sometimes, that it is still a worthy product. That is garbage and complacent thinking.

The application randomly and very frequently deletes all tab groups without warning.

It also creates back-ups but dumps those back ups in your download folder but it does not provide a mechanism for you to choose a more appropriate location.

So be prepared to have to restore your tabs from those back ups every few days. If this kind of silliness is "ok" to your thinking that's your business. But try that with Photoshop or the program you use for your personal finances. I imagine you would think differently.

The extension is not reliable and should not be trusted for use with anything important. You will lose data.

This add-on is crazy good. I used it every single day until Firefox introduced tab groups themselves, so I'd rather use the native solution than an extension, but if Firefox's tab groups seem to not work properly after all I know where I'll be coming back to.

Contrary to other reviews, I never had STG delete my tabs or anything like that. They have a backup option in case this happens, but since this isn't clearly communicated, people seem to be confused about the random STG backup folders appearing, or because they dont know about the backups they do not see a way to recover their tabs. If I had to remark on anything, it would be that this could be more clearly communicated.

Other than that, I highly recommend this extension. It's one of the best ones Firefox has to offer.

Tabs gone after Firefox close.
It happened right after all groups just deleted itself and all 100+ tabs were on main view.
BUT
I just noticed that this extension is making backups every day by default. Due to this, I was able to restore all of the lost tabs.

So am changing rating from 1/5 to 5/5.

That's literally what I need from such extension. Keep up the good work!