Good but leaves much to be desired.

Works like it should, allows you to play videos and sign in. However, there is absolutely no full screen support which is a major fail in terms of a Youtube player. It’s like going to a theater and having them leave the lights on during the movie. Secondly, it would be nice to be able to customize the appearance of Youtube. I.e. a “dark mode”. This app could easily be a five star app, but there needs to be major improvements over functionality and the UI.

Duncan Fisher about GoVid for YouTube