This add-on works well for what I use it for - downloading videos that I might want to watch several times without wasting my bandwidth. I don't use any of the other features, so can't comment on them. I've been using it for several years without any major problems; the only one I remember is a short period after Firefox changed security settings, but the work-around was ready within a week. Basically, it's reliable, unobtrusive and convenient - I really like it.