It's seems to be a good addon, but not the Top ;-) Rated 4 out of 5 stars

It seems to be a good Application, I have tried it.
But it's not as good as the "Easy YouTube Video Downloader"!! which is my Top Favorite from all.
Because with the "Easy YouTube Video Downloader" you have many video formats to choose and download.
It's the ONLY one with 1080p Full-HD and mp3 downloads also!
In comparison to this one, which has only 3 video formats to download.
Well, actually 2. (Flv & MP4)
Anyway, Good Job ialc.

This review is for a previous version of the add-on (