I can´t believe this is even being debated by a few people, Madara has been the strongest and most powerful shinobi born in the Uchiha clan, i clearly remember that the manga(can´t recall the exact chapter) said that the Uchihas inherited powerful chakra and spiritual energy, and then we have Madara stated by the manga as possessing particularly powerful chakra...even for an Uchiha.
This means means of course that he is Legendary even among the Uchiha and bear in mind that he lived in a time of non stop fighting against the Senju, he lived to fight since he was a kid until he became an adult all he knew was constantly fighting.He obviously mastered the power of the Uchiha´s eyes.
His name alone struck terror in people´s hearts, after all that who can even doubt his powers or achievements as a shinobi? The problem is that Hashirama is just too OP making Madara look bad compared to him, but then again anyone would look bad if they had to face Hashirama.
In conclusion i think some people still can´t fully comprehend that Hashirama was so absurdly powerful that in order to even stand a chance against him you had to be the most powerful Uchiha and bring the Kyubi.BUT that doesn´t mean he was weak at all, he was the second most powerful shinobi(and that means a lot).