Excellent downloader. Only freeware is used as a companion. However, to avoid conversion errors in firefox74 on Windows 10 (64-bit), you must turn off the "Always ask for download location" switch in the extension settings form.

Praticidade facilidade e 100% de funcionalidade, esta extensão sim não apenas revolve o problema de download de conteúdo do Youtube como também te fornece várias opções do que e como fazer.

I have been using this add-on for some time. Worked great.
Then I encountered:
cannot detect url_encoded_fmt_stream_map or adaptive_fmts
Tried to search for solution. Couldcn't find any.
Tried to reinstal the add-on.
That solved the problem :)

The best add-on to download from youtube. Thank you.

One button click to quickly download a video. Worked totally as expected.

Good

works well on android!

One of the few yt downloading extensions that actually work as of right now. Really nice UI for selecting format as well.

Удобно и просто )

sehr zufrieden

This addon works perfectly. To have it auto-convert videos to MP3, go to addon options, install native client and install FFMPEG and select Postprocessing -> Convert to MP3. Voila!