Excellent addon! I've got a lot of webcomics and other serial reading bookmarks, and this does a fine job of updating the bookmark with one button press. Or two, if there are more than one that might match - a little popup with choices appears, with the bookmark titles. Even works on tapas.io strips with their awful URLs!
One feature request: for Mac, the notification to say it's done is a little overexcitable - either ditching it or an option for turning that off would be icing on the cake.