Downloads are too slow.

Will not download most videos in 720

Does not work. On any YouTube video, clicking the download button just results in "Cannot detect url_encoded_fmt_stream_map or adaptive_fmts"

useless, does not work!

Don't wast your time with this add-on, go for "Easy Youtube Video Downloader Express" instead because it works !

Way too slow.

Cannot detect URL of new videos any more.
Fails to combine video and audio files. Does save video and audio files separately. Asks to install a native client and FFMPEG applications, but even after those are both succesfully installed and the browser is supported, fails to combine the video and audio files.
The video tutorial for installation is horribly poorly done, and doesn't even show the extension's option page.

I can not get this once great extension to work at all.

Doesn't let you download videos with sound or audio in a MP3 format.