This add-on is pretty good! Tho there's issues with video playback (At least when disabling the GaiaBar for some reason.) I don't really care sense it makes YouTube quite a bit more usable on my old 10+ year old hardware and now it loads nearly instantly on my second generation Intel i5 CPU, and might also run well even on a Intel Core 2 duo tho I haven't tried that yet.

Been using it for like around 3 days as of writing this, and I absolutely love it!

EDIT 2: Nevermind, I guess it was another one of my extensions messing things up. I guess it's back at 5 out of 5 stars.

EDIT: Yea, been using it for about a week, and I've been experiencing a LOT of problems with video playback on YouTube with this extension, a lot of the time, it will play but then just not wanna continue playing anymore? The video player will just NOT wanna respond once like for example I change the video quality being one of the ways that can cause this. it's so bad in fact that I have to disable the extension entirely just to even watch the video without it breaking all of the sudden, for now I'll bring the star rating to 3 out of 5 sadly, but will bring it up to 5 out of 5 again once it's not as buggy anymore. Also just noting that I'm not trying to be rude by the way, I'd still LOVE to use the extension, but there are some issues with it that makes the experience a bit worse for me.