Works great ! No bugs so far. Very sweet themes too.

It is a really helpful extension. it has many features but I use it especially to "Pin the video player when scrolling down the page", "Automatically remove annotations" and "Automatically pause videos opened in background tabs". It has many more features too but I do not need them.

I've been using this great add-on for a while now and it works well. I wish it had option to get rid of that horrible miniplayer

How do I initialize the setup toolbar?

Pretty good, love the speed control. Would be great if you could set it to open music videos with 1.0 speed and other videos with the configured speed (maybe it could check the section video's in, music is usually in "Music" section).
Other than that, the biggest issue I have with it is that it doesn't seem to be free and open source.

Really, Really like it when it works. However the menu settings are over the top complex.
Big failure right now is when the video playback is increased followed with a Volume click, the playback is reset to normal and fails to work until the video is reset. This fail is really a trial, since most videos need the sound boosted and increased playback speed.

It has been a handy little tool when I want to expand the volume for speakers who are not loud enough and I like to speed up the video when needed. I need to explore this add-on more, but so far it has been great. Thanks and keep making it better.

様々な機能があり、重宝しています
ただ、ループ再生機能が一回しか効かなかったのと、
アンケートがスキップされなかったのが気になります。
また、画質の自動切換え機能で第二希望以下の画質に切り替わらないので、どういう基準で切り替わるのか謎です。

Addon with amazing features except youtube keeps crashing

I would love it if this extension got a sharpness filter added, was a bit disappointed it wasn't one of the filter options.
Not to mention an integer based scaling option for people with 4k displays when watching 1080p videos, though I don't know if that's even possible.
A sharpness filter would help a lot though, since Nvidia's edge enhancement doesn't work in Firefox.

Does a wonderful job in most cases but does not stop youtube from auto playing in background tabs neither in firefox, chrome or opera. I think Youtube is overriding your setting somehow being the spammy ad monster it is.

One other small issue:
Sometimes videos don't start out in my preferred quality. I set it at 480p for this silly laptop, for instance). So videos wont even start because they're trying to play at 1080 or 720p instead. I noticed the same issue in Opera.