Rated 4 out of 5 stars

I like this and have been using it for years. I think it as the last safety net for XSS or CSRF.
In many slow sites, I don't allow ad destinations. I never use AdBlock etc because they use blacklist filtering which is not sufficient for rapid-growing security risks.
As a trade-off, it takes effort to use. Online payments usually require several times of allow-then-retry's to successfully complete.

This review is for a previous version of the add-on (1.0.beta12.4).