The unofficial looking Youtube app on the Fire TV and Fire TV sticks that I own works OK. I don't know how it compares to Youtube on other set top boxes such as

The unofficial looking Youtube app on the Fire TV and Fire TV sticks that I own works OK. I don't know how it compares to Youtube on other set top boxes such as the Shield TV though. For live streams, it doesn't show the chat section that you see when looking in a web browser. It also makes it hard to see the video comments/notes (which I usually don't care about anyway).