Rated 3 out of 5 stars

works, but you have to keep the youtube tab open of the song you're trying to download for the entire duration of the download.... so it works, but it's a little fussy. i see from the webpage that you're working on fixing that, though.

This review is for a previous version of the add-on (2.7.1.1-signed). 

You can download a pre-release version on www.glimmersoft.com, and it should be up on mozilla.org in week or two. Thanks!