Madara. Worse I can give to sasuke is his MS self who wanted to destroy the village, killing sakura, etc.
Madara on the other hand, ruined Obito life and lead Obito to doing all what he did...
Sasuke is probably colder because he thrives on that persona. Madara seems to have more personality. Both of them are very emotional though, like all the Uchiha. It was like Tobirama said, they love greater than anyone else, which is why their emotions get the better of them when they experience loss.