I have been using this add-on for awhile and if I run into questions, the creator has always responded to my questions. Glad to have this one!
5/21 update - this developer has always been on top of all youtube changes and quickly resolves issues. Still a 5 star!

Great little extension. Please donate, people, if you use it. I did.

It's works.

teleio

Works very well, I mainly download short movies and the occasional live music event. quality of downloads is excellent, and play perfectly in VLC.

Works mostly very very well. Very useful extension. Excellent support. Have been using for about 1 1/2 years. Thank you!

Thanks a lot.. very nice and helpful.

seems to work good so far

Extension très utile qui m'a rendu de nombreux services, elle me convient parfaitement, merci !

Love this- one of the easiest I've found and haven't run into any bugs yet.

great product, easy to use!

Excellent this add on Firefox browser, I recommend it. And very useful, like me so much, once again is reliable and smart! Now is more effective and faster! Enjoy it dear friends. Thanks

Simple and consistent

Excellent! As long as they stay up on the bugs, we're cool! Be sure to donate!

Works like a champ. Looks like part of Youtube. Very nicely done!