Not bad. But it would be so much more useful, if all existing (user-created) tab groups would be located on top of the tabs (being tabs by themselves): click a group tab, and it opens below it all the tabs of their included web addresses (opening here means making visible as tab, not loading each web address - that happens when the user activates that tab).

Works great to save memory, but has some BUGS. One of the more anoying is, sometimes when you jump from one to another group, one or two tabs from previous grup apears in new selected group (majorly near to last active tab). Another BIG bug is to loose tabs after close FF and shutdown the PC, one day to other loose almost al my tabs and only 4 appears in current window. Only one time happend (lucky me). BR.

A good effort, still plagued by the bad user interface and some stupid limitations.
WE WANT TO MOVE TABS AROUND! I understand it might not be possible the old Tab Groups way. Still, you can make it possible (now is almost prohibited) by this sooo simple tweak:
MAKE THE TAB URLS EDITABLE AND ADD A "NEW TAB" FUNCTION at the Edit group tab and we will simply COPY-PASTE THE URLS without having to leave the active tab group. IT IS THAT SIMPLE!!!!
Also, it would be nice if you made possible a scheduled Export function, we wouldn't fear that we could lose our tab groups for some weird reason.

I finding replacement after Tab Groups addon (https://addons.vaultpit.io/ru/firefox/addon/tab-groups-panorama) like many people using FF. But for this time there are missing many important features like keyboard shortcut, global preview (I using mainly for finding specific tab).
It addon is good, but its not enough for me now. Maybe use later.

Nice - but missing an option to NOT load all tabs when switching to a group (e.g. option like load only last active tab of group). This makes switching between groups with more than 5 tabs really slow.

Good start. I miss a keyboard shortcut to easily switch to another group.
It would be better to keep the hidden groups in cache instead of having to reload the tabs each time we switch to a hidden group.
I have to re-log in and confirm leaving the page for several websites.
Containers are not respected.
Thank you.