Really like this add-on and I get a lot of use out of it! If there's one improvement I could suggest it would be to allow users to add their own icons for new container categories. As it currently stands, it seems like you're stuck with a list of default icons you can choose from.
But that small gripe aside, this is basically a 5 star add-on that I'd highly recommend to any security-conscious person. If you'd install uBlock Origin, you'd be a fool to miss out on this.