buckworks - 1:04 am on Nov 18, 2012 (gmt 0)

the target audience would instantly know what the site's about

I'd consider that a major point in favor of the "obvious" domain name. It would make promotion easier, forever.

Something else to consider would be how the two domains would come across as a component in longer URLs.

Which domain would make a better impression in a context like

"Example.com/directory/sub-directory/long-winded-article-title/

I like OnlineLeben's suggestion of an AdWords test.