Forum Moderators: open
See if -
The page that lists you ranks well for terms that it apparently promotes.
The site is online for atleast 2 years (My personal benchmark)
A significant % of its pages are empty - Not good.
Editorial quality. Whether your closest competitors are listed in the page you will be listed, or are they thinly related.
The directory runs other sites with same content.
If the directory uses any SE or dmoz feeds to populate the pages.
Is the entry for life or do they charge per year?
Mind you if the site is very useful and established, $25 seems very good value - even that rate paid every year is worth it, as long as the traffic is there.