Worked for bringing over a thousand tabs over from Chrome because google insists on trying to kill adblock.
My only real complaint is the layout is infinitely better on Chrome than Firefox, the Firefox layout is just a basic list broken down by window while Chromes is an actual usable program you can organize things in, it's basically the same layout as the bookmark manager in Firefox. The Firefox version is also missing over half the options page from the Chrome version.
In my opinion, it's useful as a way to move tabs over from Chrome when swapping browsers but not as an actual tool for use with Firefox, unless you're swapping to Firefox permanently don't bother with it and just get the Chrome version. Particularly since it hasn't been updated in over two years at this point and the Chrome version was just updated less than a month ago.