I like this DL'er because of its ease of usage, and it seems to be the only DL'er that actually works on YT without having to take all day to 'aggregate'.
I emailed the author about the recent problem with YT coding change, thus taking the 'green rectangle' off of each YT video. I appreciate the rapid response (less than 2-hrs). telling me they are aware of the problem and have submitted their solution to FF for review and their next update.
Most of the recent 1-star reviews pertain to this situation.