Its great but has a bug in it like a month long, so maybe since last update,even reinstalled firefox to avoid the mistake on my end!The bug is that when you open youtube that any specific page will be continously loaded so that its impossible to search,play a video or do anything ! So at the moment i disabled this Add-On...hope it will be fixed soon!
Five stars cause it was great and im sure it will be working again when the bug gets fixed !