With how many of these types of extensions have been failing, it's nice to find one that actually still works (And really well at that). All the features I'd need are here, and they work great for me. Loving the cinema mode the most. It was the only reason I used YouTube Gaming, but with how many basic YouTube features are missing from YouTube Gaming, it's a pain to use sometimes. Love that this basically brings the best of both worlds plus more.
Edit: Took one star away. The Ad-blocker doesn't work as intended. I run uBlock Origin on most sites, but wanted to see if I could get this one working on YouTube so that I could whitelist channels I still want to support. However, while the channels that are whitelisted properly show ads it also breaks the enhancer toolbar below the player (which won't show up anymore). Also, on channels that are not whitelisted videos simply will not load at all. If I grant permission all ads will be blocked as intended, but the whitelist feature is not available when you block ads before loading (from what I can tell). So, that defeats the purpose of me using Enhancer's Ad-blocker. Oh well, I'll just stick with having uBlock disabled for Twitch and YouTube.
Windows 10
Firefox Quantum v64.0