Rated 4 out of 5 stars
Youtube MP3 Podcaster 3.7.0 with EN-US SeaMonkey 2.33.1 (German Language pack) Gecko/20100101 Build 20150321194901 (Default Theme) on German WIN7 64bit
But: Screenshots here do not match with my experience, should be updated so that everybody can know that the Youtube MP3 Podcaster Icon needs to be clicked to bring up a dialog with lots of download options.
Bitrage 256 kBit/s seems to be default and creates rather big .mp3 files, I will check whether quality really is better. For a cell phone cam movie like https://www.youtube.com/watch?v=qLsVKSjkziY that is some kind of overkill.
The add-on does the mp3 conversion after having done the download for the complete movie, what causes rather big downloads (70MB for a 4 minutes music movie), what might be a problem with slow internet connection.