the phantom 315 reflector uses 95% European hammer tone aluminum, unlike the sunsystem that uses mostly smooth specular reflective surfaces with hammer tone only in the corners.
the hammer tone will give better diffuse reflection compared to the specular that will be more focused. In other words better light distribution uniformity with the hammer tone.
I myself prefer diffuse hammer tone, less chance of focused "hot spots" and less likely to reflect much light back onto the lamps arc tube.
but to each their own, its a big world out there.
I hope if Sunsystem does a light fixture comparison they use a third party lab, with proper testing equipment like a photogoniometer, and not some weak ass single plane test in a tent with a hand held light meter.