This extension simply works! It's intuitive enough to need no more than a simple explanation - which they provide initially; and you can save as a bookmark (I could). AND it doesn't take very much space - while providing the full quality! ...Based on which quality you choose. Since mp4 at 1 of the available qualities AND choosing 1 of 2 download speeds (for mp3) worked: I assume all the formats you can choose from, also work.
And finally: This add-on is not intrusive with ads.
I'm pretty completely pleased. I think it is complete enough to not need anything else. Since it has all features and options I truly need, and could reasonably ask for - AND since these work completely.