Mostly, it's kinda hard to manage a huge amount of groups and tabs, as you can't multi-select groups and tabs. It's really hard to move tabs around groups, organize the order of groups, delete multiple groups at once, etc. It's not as practical as it should be. And I think the UI is kinda outdated, though that's just aesthetics. But also, it is the only tab group extension I've seen that saves this much memory. You open a group and it doesn't load 60 tabs unless you specifically tell it to. For that alone, I don't switch from Firefox to Chrome (because Firefox mobile fucking sucks, at least on MIUI). I also like the praticality of deleting tabs from a group. You open the group and close the tab normally, it counts. For some reason other extensions are more convoluted than that, which is fucking nuts. And lastly, the backups are hit or miss. The automatic and manual local backups are great, but the bookmarks are really weird to me. Like, why doesn't it synchronize with current tabs (or at least have an option for that)? Instead, it adds the initial tabs and then keeps adding new ones infinitely. It's looks like a mess and I see no point in it. For me to get all my groups, as they currently are, as bookmarks, I have to delete the STG folder and wait for it to save again. That or I'd have to add every single one manually, but that's not viable.

I'd give it a 3 for lack of practicality when organizing shit, but it keeping me stuck on Firefox because of how useful it is makes it a 4.

Easy and simple. Love the unload from memory feature.

do you ADD / ADHD? do you have trouble tracking tabs, organising them, grouping them, etc? my DEITY this has changed my life! i still have ridiculous numbers of "i'll get back to that later / when in the mood / when i'm doing that thing that i need to refer to this tab or group of tabs", TABS... but now they're organised. with an S. UK/AU English. Now to find out where i can donate, it is really that good.

Most useful addon/extention in the store!
IT IS A MUST HAVE & SHOULD BE NATIVELY INTEGRATED IN ALL BROWSERS!!!

However i have some recommendations:
1. More settings for customizing the manage groups view.

edit: And we need Subgroups :D

1.1 Fold/Unfold a specific group or a pair of groups (fold custom topic 1 only) the folded group now only shows custom number of entries [i have too many groups they dont fit onto my screen at once, even with my 1,20 meter wide monitor+second monitor setup lol]

1.2 Highlight tabs that are currently loaded (text color+backround should be both customizable to avoid people in dark mode or with dimmed screens seeing the difference)

Fantastic interface and I love the backup feature.

When it works it's awesome, one of the most useful extensions. But when it doesn't work, it just destroys everything. I had over 200 tabs across 15 or so groups. I opened firefox today and all the tabs are gone. The groups are there but they are empty... and this isn't the first time this has happened. So if you want to organize your tabs you can use it, but at some point it's just going to break and you will waste a lot of time opening tabs again.

Very useful extension for organizing my (many) tabs. I did find that the 'load x group' hotkey options such as 'load next group' were broken; I would like to see that fixed.

All tabs were reset at a random moment.

This extension is a must. Its features should be built-in into Firefox.

You can use it in a sidebar thanks to the "Show sidebars" button that you can add from Firefox customization. That gives you not only tab groups but also vertical tabs that have become something essential to me no matter the browser I use.

I normally create and delete groups dynamically without skimping. Every time I start doing something I create a group just for that (even if at the end it only required one tab) and delete the group afterwards.

Very intuitive UI, supports color codes and regular expressions! Feels awesome!

Unfortunately Firefox doesn't have a very good Profile Manager, the onboard one is very primitive (unlike other browsers).
I tried this instead, and it works well. I have different subject areas arranged in different Tab Groups. It is easy to stay organised, and switch between subject areas.
Works really well for keeping your Tabs organised.
Has a built-in backup tool which I regulalrly use!
Update: I now use shortcuts to open the 'Groups Manager' for ease of managing, also for a manual backup, before I make any changes.
Great tool for organising different subject areas while you're working.