Rated 4 out of 5 stars
Add-on works fine. This review is more about StartPage search engine. Privacy search, search results by date, image and video search.
Frequently gets not specific results, contrary what you asked about. Tip: use advanced search to make sure that search was done not for "any of the terms" instead of "all". If this fails, use a different search engines for better results.
Despite all of this, Ixquick and StartPage are my search engines of choice for years.