I was always interested on who was the best in DGSD. I somehow think that Xu Zhu has an edge over Xiao Feng.
What about Guo Jing vs Yang Guo by the end of ROCH? They were both named greats, but I think Guo Jing would win due to his experience and the Nine Yin Manual. If they were both in their prime, i would still say Guo Jing has an edge