Love the functionality this add-on provides (especially the custom themes and ad block are great), however sometimes it freezes the tab. Happens about 3-4 times a day with admittedly very heavy use, so it's bearable but nonetheless annoying.

I use only the boost audio and loop button, with this settings, it's really odd to have just two button on the bottom of the page, it would be better to add it on the player toolbar itself !!! (or like the "maximize video" userscript from icycat (冻猫) = attached on top right of the player and visible on hover only)

Overall good, so far. will be testing for myself. the fifth star is in queue!

Nice

good job, thank you

Works well, except volume control doesn't work until I refresh the page, or switch to another video.

would be nice if you could add an option, to show the rating (in percent) of a vid under the thumbnail. the rest is nice

add classic youtube design theme

nice tweaks for youtube. but that background tabs really wont stop playing u need extension background playback fix.

recently the miniplayer still appears despite being turned off

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.