I've tried a number of extensions to find the ease of Chrome groups in Firefox and thus far this is the best one I've used.

I particularly like that each tab group functions as it's own instance for cookies. While it is somewhat tedious to set up services across multiple tab groups using a password manager in conjunction with this extension does speed up the process.

I would love to see tab groups sync across instances of Firefox as I have needed to set up the tab groups in each instance I use. Again, once set up, it works flawlessly and is intuitive on assigning newly opened links either to a specific group or otherwise.

Fir anyone else seeking a Chrome-like experience I would recommend giving this service a shot just be aware that it does have a few UI quirks that you'll need to familiarize yourself with. Specifically reordering tab groups is, at the time of this review, found in Settings > Options > Sort Containers. It would be very nice to be able to drag the containers for ordering purposes.