The links are currently split up into three types: AX Groups, AX Blogs, and AX Links.
The reviews use a 15 point scale and three categories:
Usefulness: How helpful the site is.
Design: How pleasing the actual site design is. Does it burn my retinas or annoy the heck out of me when I visit?
Return Potential: How often will I return to the site? How is the site updated?