ADWARE—READ THE FINE PRINT! Rated 1 out of 5 stars

Yes, technically it does allow you to get themes. But at the cost of redecorating your browser with their adverts, allowing them to insert spam in any form in your browser, "hijack" it, reset your searchbar, homepage, themes, add advertisements, etc. I tried it and was NOT happy with it.

I wanted to link to the 10th section in particular, but there wasn't a table of contents. So here's a piece of the agreement that shows what I'm talking about:

"10. Third Party Content; Advertising.

[...]

Brand Thunder may deliver third-party Advertisements in the form of coupons, price-comparisons, display media, affiliate links and other links through means including but not limited to the content of any web page accessed, plug-ins, add-ons, or the browser itself. Advertisements may be injected to overlay the page or inserted directly into the page content. User hereby acknowledges and consents that Brand Thunder may alter the content of any web page accessed for the purpose of displaying Advertisements. Brand Thunder does not endorse and is not responsible for any information, materials, products, or services contained in or accessible through Advertisements. Accordingly, your correspondence or business dealings with, or participation in promotions of, advertisers found on or through the Service are solely between User and such advertiser. ACCESS AND USE OF ADVERTISEMENTS, INCLUDING THE INFORMATION, MATERIALS, PRODUCTS, AND SERVICES ON OR AVAILABLE THROUGH ADVERTISEMENTS SITES IS SOLELY AT YOUR OWN RISK."
(above text copyright Brand Thunder ©)

Full text @ http://brandthunder.com/eula/

This review is for a previous version of the add-on (1.6.4.1.1-signed).