I've been using this on premium for a long time now and over the years I have had some issues crop up. Usually it's right after YouTube has a big update and they changed something that ends up breaking the downloader. I just shoot the dev an email and he's always got it fixed within a couple days.

It's a great tool, seamlessly integrated into the normal user experience of YouTube. Super easy to use. And stellar customer support when issues appear. Well worth the $10