This is the best Youtube video downloader I've tried, and over the years I have used a lot of them. Two very important things I love about this plugin are that they keep it updated, and fix bugs. There will always be bugs or things breaking in software, especially when it works with a 3rd party service as in this case. But so far they have released updates to fix any issues. Another feature I love is the option to download as mp3. There are so many videos that really add no value visually, and could just as well have been made as mp3s. So why download a huge video file when you can just download an mp3? This add-on makes it easy to do just that.

There is a lot of software that is advertised as 'easy'. This one truly delivers on that. I can't imagine how they could make it any easier. It's so good that I have donated to support them, and I will do so again as well to give them some support for making such a great add-on and keeping it updated, fixing bugs, etc.

UPDATE: 2 years later and this is still my favorite and most used add-on. Thank you to the developer for all the hard work that goes into upgrading this every time youtube changes and breaks something!