Extremely useful tool, much used by myself. But experience a couple of glitches, at least when downloading from YouTube, by far my most used source.
1. After downloading several videos in succession, downloads fail. The work-around I have discovered is to cut the connection and change the IP# via my VPN. If that fails, a reboot makes it work.
2. Many videos are available offering dubbing in a variety of languages, the default usually being English which is what I listen to (or occasionally French in which I am fluent, if that happens to be the original). However I sometimes get a succession of recordings dubbed in German! I have no knowledge of the language and have found no solution to this.