I wanted to call attention to a series of blog posts that Alain is writing over on the VRT blog about the ContentIQ test and ClamAV's results with that test. Enjoy:
http://blog.talosintel.com/2012/02/clamav-vs-content-iq-test-part-1.html
http://blog.talosintel.com/2012/03/clamav-vs-content-iq-test-part-2.html
http://blog.talosintel.com/2012/04/clamav-vs-content-iq-test-part-3.html