NASA set up an evaluation of several comparable tools and guess what? My dad's tool scored best and they bought a license. Congratulations dad!
You can get a copy of the paper on this evaluation and corresponding presentations here (category "Requirements Analysis"). It's titled: "Evaluation of Current Requirements Analysis (RA) Tools Capabilities for IVV in the RA Phase". (You have to leave your name and email address to download it.)
As you can read on my dad's site, he's (a.o.) working on preparing Requirements Assistant for the Eclipse environment.