So there's quite a few things about this addon, some of which aren't quite the fault of developer, but some of which definitely are.

The addon works, but very slowly. We're talking about anywhere between 15 minutes to literal hours, depending on what you're doing. That's because developers download the video from youtube to their own server first, convert it to the desired format, and then offer you to download the converted video from their server. Their server is probably hosted on a free tier of a hosting service (ads pay close to nothing, and donations are also close to nothing).

If that's where the problematic things ended, I'd give 4 stars ... despite downloads being ultra slow.

But there's some things that range from 'mildly' to 'wildly' problematic.

* This extension says 'Yotube downloader' on the store page, but 'Youtube downloader plus' once installed.
* Interface presented in the screenshots is nowhere close to the actual UI. Screenshots show download menu being contained in the extension's context menu. In reality, extension opens a popup window.
* The extension doesn't mention that for youtube, 'video' download options only download video without audio. While hardly surprising to anyone who knows how youtube works, I don't think it passes the grandma test.
* Video download options offer 1440p and 4K options even on videos that are available only in 1080p or lower, and offer no clarification on what happens if video isn't available in 1440p/4k. Do you get the next biggest video? Do you get 1080p converted to 4K?
* The UI does not differentiate between native audio formats (for youtube: m4a, aac, opus), and the formats that need to be converted to.
* Downloading audio-only in youtube native formats worked (opus).
* Converting youtube videos to mp3 didn't work.

and, saving the most problematic one for the last:
* when you download the converted video, the extension opens a new tab to a site that uBlock Origin labels as "badware".

crap

Это просто и эффективно.

Its a great tool and handy as all it takes is a little extension know how and you are all set!

It is a perfect and quick app. I am delighted. Thanks

This extension is an absolute lifesaver for a lot of things I couldn't download off the internet. 5/5 recommended

Excellent downloads, quick and easy; good quality!!

Haven't yet tried all features, but seems to do all it claims.

does not work