i have had a look through both, but they are kinda hard to judge, if every mirror was absolutely exacting in its manufacture, then it would be easier to give a resounding verdict.
I thought the GSO was good, but i thought from the SW's i have looked through that they where ever so slighty better.
but at the end of the day it comes down to personal prefference, collimation etc.
i am sure there is nothing much in it.