Both have dark chakra, got praised by Kurama, acquired EMS, both look alike, both are very proud of their powers and their clan etc.
However, the only difference is that Sasuke doesn't lack hatred
He is more arrogant, more pissed off version of Madara, and has a genuine reason for his hatred - unlike Madara who's unjustified hatred was born out of petty jealousy for Hasirama, and not being chosen as Hokage.
Thus I see Sasuke rapidly growing stronger, because hate = power for demonic descendants of the Juubi, which is the Uchiha, and surpassing him in the future.
However, the only difference is that Sasuke doesn't lack hatred
He is more arrogant, more pissed off version of Madara, and has a genuine reason for his hatred - unlike Madara who's unjustified hatred was born out of petty jealousy for Hasirama, and not being chosen as Hokage.
Thus I see Sasuke rapidly growing stronger, because hate = power for demonic descendants of the Juubi, which is the Uchiha, and surpassing him in the future.