I've rarely had any problems with this downloader. I'm wise to how the YouTube downloader game works, if the add-on doesn't work then Youtube changed their coding thus breaking the add-on so the developer has to sift though YouTube's code to rewrite their add-on's code to make it work again.

TL;DR If the add-on don't work, it's stupid YouTube's fault. Hang tight, Dishita's got you!