The extension is really good and well designed, but I'll have to subtract one star for the lack of Sync synergy - in this day and age it's unacceptable imho that one should have to go back and forth between different browser instances in order to manually copy over the various extension settings.

Also, on Linux, when clicking on "Export Settings", instead of a file download prompt one gets the JSON file opened within the browser. If it's not something to do with Firefox's limitations on that platform, It should probably get fixed.