Madara hands down. For one thing, Madara actually engaged in combat with the Bijuu. He fought all nine at once, and even though he got his ass slapped around for a minute, he came back around and slapped all of them around. Then he literally put them all on a leash and took them by force.
Sasuke didnt really do anything special outside of placing all nine under a genjutsu with one glance. The Bijuu weren't hostile towards Sasuke, so they were all off guard. Sasuke just stabbed them in the back basically. Not much of a feat if you ask me.