Can't always detect videos for downloading, but it's the number one way I download a video if it's an option. I can't think of any real problems I've had with it, except some video sites stream content and you have to keep it playing while it's downloading or the site stops sending the data, I guess. Sometimes the video will be a bit choppy, but that's so incredibly rare I'd wager it's a site issue, not the addon. Give it a try, I doubt you'll regret it.

EDIT: Taking off one star for constantly opening up new pages when it updates. I DO NOT CARE THAT THIS ADD-ON HAS BEEN UPDATED. DO IT WITHOUT TELLING ME. Could literally never update again and it wouldn't make a single iota of a difference to me.

Also, be aware of the review mentioning QR codes is specifically referring to a form of video download called "ADP" and they likely tried to download something off YouTube. YouTube is NOT supported as a download, likely out of cowardice from the developers that they'll have Google on their rear-ends over it. You can download those with any basic YouTube to MP4/MP3 site, instead.