Glenn, I used to work for a concrete company that was a dealer for Logix Styrofoam concrete forms, and about 3 streets down there is a house that all of the exterior is these forms with concrete. Its a really slick system to use, and is in my opinion worth the hype they have in it. My boss used to say, that by the time you frame and insulate the basement, you are just about even with using the Logix forms.
However for this job, just being a garage, I don't think there would be any advantage to them, (unless he wanted to just make a basement and then pour the garage floor over top, giving him a workspace underneath
Justin