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
I like OnlineLeben's suggestion of an AdWords test.