Edit: Disregard the review below. Previously I gave this three stars, but the add-on hasn't been updated in two years, and the beta versions I mentioned below have been removed. There's no indication that the developer is taking any steps to fix the issues with this add-on. Therefore I've reduced my rating to one star.

Previous review:

Pretty nice! This makes YouTubing a much less chaotic experience! Only gripes for the current release are: 1) "Hide Related videos and sidebar" also hides the playlist sidebar when you're watching a video in a playlist; 2) "Hide comments" also makes it impossible to view playlists themselves.

The beta versions I've tried (0.4pre3–0.4pre5) fix the latter issue. However, they also move the preferences from a toolbar button to the add-ons page. For this type of add-on I think that's a poor decision. If I'm watching a video, and suddenly decide I want to see the sidebar, I don't want to have to pause the video, open a new tab, and navigate to preferences in order to do that, and then do the same thing again when I want to hide the sidebar again. This is the kind of add-on where you should be able to change preferences on the fly.