It would be really cool if this had an inbuilt downloader, but it doesn't. I used this because YouTube started auto-setting my quality and this addon was said to stop that. But even if that problem is fixed, this program's miniplayer is so excellent I'm not going to stop using it.

Another feature I really dislike is that it automatically enables controlling the video speed with your mouse, which I have never once intentionally wanted to use, only unintentionally scrollwheeled and set it to 0.75% speed. There are barely any times when someone needs to change the video speed, so this should be disabled by default (I at least think I've finally disabled it now).