I find this extension to be an excellent replacement to YouTube's Collections feature that YouTube removed, and it works more or less as it should with only mild difficulties from time to time. When there are difficulties that are typically caused by user inexperience, but even this is addressed with tutorial videos.

I do, however, wish that there was a mousehover/hoverbox when my mouse is hovering over a subscription group, because the YouTube sidebar/menu-bar is so short, many of my subscription groups have their names cut-off, and without a way to widen the YouTube sidebar/menu-bar, the only way to see the full name of my groups (some of which may have similar names) is with a mousehover.

Otherwise fantastic work, my compliments to the developer