This add-on is basically the only reason I use Firefox, and it has so many issues that I frequently contemplate leaving it.

Syncing across multiple devices (Windows, Mac, Linux) just doesn't work. It doesn't. On Windows I have 4 duplicate "Home" containers that reappear every time I sync. On Linux I get over 10,000 "Personal" containers. On Mac, who knows. I delete the extra containers (or try, on Linux), and next time I sync a device, they're back! It's maddening!

Now on Linux I've uninstalled and reinstalled a dozen times, and it won't add my custom groups. Where did they go? Why is this so hard?