There are many ways to evaluate a directory. One quick way that I will share with you, is to determine if Google is crawling the snippets that the directory has been creating for listings. How may you ask? Simple - search the snippet in Google and see if the directory listing shows up.

You will probably find that some directories show up and some don't. Also, I wouldn't stop at this, you'll want to do additional research on the directory before you go ahead and submit your site.