Besides the fact that they were all pretty horrible, any vintage helmet based on styrofoam would be useless by now. The Giro Reverb looks quite a bit like a cross between the old Brancale and MSR helmets, but probably works better than either. Might be a bit toasty in the ozzy sun.

I recently had the same dilemma, and decided to suck it up and get a basic black modern Giro helmet. It kind of looks like a Kucharik hairnet if you squint...