I am also building an application that could use this service. So I tested TextRazor and the results were not good on two random articles I processed with the service.
I really want this to work out, because my application needs this kind of technology to be reliable and accurate. I just processed the article at the link below, and the word "Tesla" was not captured as one of the topics. http://www.teslamotors.com/blog/most-peculiar-test-drive-fol...