This extension actually works, however, It is almost impossible to locate the real downloading URL location/button because the author has liberally added adverts which look as though they would be the download URL for this (good) firefox add-on. For instance, I just received an email touting an improvement to this add-on, but was unable to locate the download url to it.
UPDATE: improvements no longer have to be downloaded, since they automatically are installed by this extension.
If you can find the URL for the Author's support email, you will actually get a response in about 3 days. My experience is that if you don't give up after receiving the first, generalized response, you will eventually be very satisfied by the author's support, e.g., it took me 4-5 emails to get exactly the information I was seeking.

Works well, except that one needs the paid version of it in order to download at decent quality.

Good extension.Thanks.

I have the free version and most of the time it works great. Sometimes it doesn't work for one reason of another, but it normally gets fixed within a week. I wonder if the pro version has the same problems? If it doesn't, I would probably pay for it. Regardless I would recommend this add-on, just try to be patient when YouTube changes its coding and the add-on needs to be updated.

Its quite but refuse to donwload sometimes

16.13 not work.the button is invisible

สวัสดีครับขออนุญาตใช้ส่วนเสริมนี้

best option i have so far for downloading youtube vidoes

Oops! I clicked too fast. That was supposed to be a 5 star. I love this extension. Use it all the time. It's amazing to me that one person is managing and updating it so quickly every time YT decides to change their code to try to stop video downloads! Read Firefox user 16885901's review. If you have a video download problem it's probably YT. And you1ll get an update pronto from Easy Youtube Video Downloader. :)

After a too long time of troubles, this extension works fine again.