I absolutely love this add-on. This is the only youtube add-on that ALWAYS stays enabled, before this one I would disable/enable add-ons when needed [& restarting FF].
1 problem though is that the 480 res is never available - 720 is the highest I use & 360 res is too poor. I find some youtube clips are too big @720 res - I'll try to disable WEBM format, maybe it is blocking the 480 res from the list.
Thanks for the add-on!!