Unusable in its current state. The dev is still working on it on GitHub tho, so it may come back.

I mostly just wanted this to blacklist channels, cuz blocking them doesn't seem to work.

Disable hight frame rate feature doen't work in both old and new version.

Works flawless. Although not all features from the older versions are implemented, those which are implemented work flawless, as expected from the author who does an amazing job. I'm looking forward to future development.
Too bad most people give the rewritten version of this addon a negative feedback, but the fact that he now uses a Firefox API to more reliably inject changes to YouTube video player is a very good development. This strengthens this addon and will lead to a much better user experience in the end. Remember when similar addons which claim to disable autoplay actually only pause the video after the page was loaded and if you were unlucky the video was played for first couple of second anyway? (until page loading was finished) This will not happen with this improved injection method. It is really great. I enjoy this so much to never have to worry about any videos starting without my permission. Furthermore this will strengthen Firefox as a browser because this new API is only available in Firefox, not in Chrome.
I'm greatly impressed that the author had the courage to overthrow all legacy code and start a new version of his addon with improved techniques. This is something a lot of developers are afraid to do, and therefore their software dies in complexity.
I cannot understand why people complain because the old addon was broken anyway by recent YouTube changes. So there was nothing to loose.

Used by over 0 million people, this is a nice screenshot for this add-on: D but joking aside, it's a good addon and does its job

This app has stopped working on Youtube for Firefox Quantum but works on Google Chrome. Please fix this App for Firefox Quantum.

Going back to previous version... Lets just say that the next time I'll update is "coming soon"

I went back to "Version 0.2.5" and everything works as it should ;)

The creator seems to have rage-quit and removed nearly all of this plugin's features.

It's too bad. When I saw that there was an update to the plug-in I was excited. This was once my favorite plug-in and I was hopeful that it had finally gotten some much-needed love.

Now, there's no bugs, but also no features.

Youtube не працює, якщо відкривати відео з gmail.

Youtube does not work when opening videos from gmail.

Fair warning for anyone thinking about using this addon, it will hold your browser hostage if you ever dare to disable and uninstall it. YouTube will not work even in safe mode if you disable this addon once installed. It's highly suspicious and I recommend that everyone reports it for investigation by Mozilla, as the developer so arrogantly wills us to.

Im using old version only youtube main page isnt working with blacklist everything seems to work on new youtube. 5 star addon. I didnt like they way you changed version but it wasnt a problem revert to previous version and everything is ok. I'll switch to new version when blacklist works again.

I recommend this add-on 👍