I think Madara will show his face first out of the two of them.
Kakashi already showed his face once when eating at Ichiraku and Sasuke,Naruto,and Sakura missed it. But the guy and the girl behind the counter saw his face and seemed to be glamorized and in love with his face.
So I would say that Kakashi is extremely handsome and does not want unnecessary from women and men alike because of his good looks and does not want to be known as the hot guy but to be known as a fierce Shinobi. he does not want the same problems Sasuke has with annoying women such as Sakura,Ino,Kirin,and Mizukage.