Its pretty good, and i like its features a lot, but unfortunately i have encountered bugs.

Most notably, the icon bar/buttons under the video seems to just.. disappear. Refreshing the page will not fix it. I noticed that disabling the extension, then refreshing the video page, then enabling the extension makes the icon bar re-appear. But refreshing the page again makes the bar disappear again! Its very annoying and very inconsistent, and it has been happening for a long time.