So what do you think was the difference between Madara and Hashirama?
Hashirama came became to be known as the God of Shinobi and the most feared man of his time.... while Madara just became a guy who Hashirama defeated, and not really respected... SO WHAT DO YOU THINK?
So here is my analysis of their power:
Hashirama was always superior a level. Ever since they met, Madara was trying to throw a stone across the river, but couldn't.... while Hashirama was already capable of doing it. This basically foreshadows that Hashirama was always a step ahead of Madara.
Later on in their VOTE fight..... Madara believed he was ahead of Hashirama , since he had Kurama under his control .. but then Hashirama does the Buddha technique and fodderizes kurama and PS..... again proving he is 1 step ahead of Madara.
This leads me to believe that there was always 1 or 2 level difference between Madara and Hashirama. So currently people say Edo Madara > Edo Hashirama.... however I disagree..... You can't say one is stronger then the other now.. when Hashirama's powers weren't even completely shown.
Now as far as their presence in Edo tensei goes... Hashirama's presence makes him LOOK stronger... Madara has his Mokuton.... but he doesn't have Hashirama's body. He doesn't have the intelligence, the scroll of seal jutsus and so on.