You have to pay for anything useful to work, the reason makes sense, so not 1 star.
Also im noticing what looks like lots of bot 5 star reviews???...
The UI is pretty nice, so I would have used it more if it ... worked, ya know.

keeps showing nonsense notification when i don't even want download anything.annoying

used to be good, but now it needs a "PRO" version to download anything with a decent quality

If you want to download HD it asks you to pay for this. No way, I deleted this add-on right away.

The addon works well, but the "One time payment" claim is false. I've been asked 3 times in 3 years to donate as he removed my access. Should be more straightforward if he wants yearly donations instead of claiming a lifetime payment.

"Offers" 1080p downloads. As long as you pay them.

It actually is very easy to use, but sadly the downloaded video has significantly worse quality (everything clearly gets blurry) and it displays as lower frames per second than the actual video. 60 fps gaming video looks like it turns into 40'ish fps.... Not worth it to get a laggy crap quality video.

the new popup on the right when i watch a live stream sucks ....

2 stars because it works but has invasive pop-ups that force a tab switch.

Download button disabled suddenly without any action on my part save for refreshing youtube webpage

Developer updated their product. Product still doesn't work (for me). Don't get me wrong, the product functions on "normal" videos that aren't aren't altered upon upload. But if the uploader alters the video in any fashion which changes how YouTube indexes the said video, the downloader fails even function. The interface won't even show up on the page.

Example: Say a video goes up and you save it to a favorite playlist. The uploader than decides to change the video from "public" to "unlisted." Because of how it's indexed, it throws a HTTP 410 error. And while the URL itself will still redirect to the video in a browser, the downloader (and every type of of player/recorder I've tried) all throw the same code. So the short answer is you'll have to screen capture videos if you follow creators that make a habit of this. I'm not sure if the developer has a workaround solution for this type of behavior which Mozilla (and browsers in general) account for it at the application level when it parses info through the OSI model that they can build in to their addon. It would definitely be nice.

Does not support downloading of videos that are behind age gate (even after you confirm your age to youtube).

This downloader keeps opening new tabs for its website on by Firefox browser. I'm not interested in the website for "Easy Youtube Video Downloader" . The latest page on their website asks for a cup of coffee. No kidding. No option to opt out of receiving such notices. No way to unsubscribe.