Hashirama is an elite shinobi, who has the ability to ascertain his opponent's strength. Not once, he said he wouldn't be able to beat madara, whereas in the case of obito, he frankly states that he (Obito, after becoming jyuubi's jinchuriki) has become stronger than him (Hashi). During the last battle, after defeating madara, he also stated that he himself was the only one capable of defeating him. And similarly, he gladly accepts the challenge put up by madara in a playful manner, even after seeing madara's rinnegan and his fusion with hashi's cells, because he knows he can defeat him, even though it might be quite challenging. So, it would be wrong to conclude, who is stronger, just like that.
As for the unlimited supply of chakra and stamina, it is not only true for edo madara, but also for other edos as well. No matter, how much they fight, they won't get exhausted or run out of chakra, as it was mainly aimed to clear up the battle field, when the jutsu was developed. However, they will suffer the damages caused by external attacks, but regenerate overtime continuing the fight, if their souls are not sealed properly at the right moment.
