I don't like uchihas the philosophy behind their clan is not something I agree with so I have never liked their clan, as a result I may be more critcal of uchiha.
Despite I will say this Edo Madara is at the very top, the only people that could beat him are.
Tobi (we don't know fully what he can do, but what we do know is that he has shown he is at madaras level pre Edo, the fact that he never seems like he is fully trying says something)
Minato with Karumas chakra (Simply because he needs huge amounts of chakra to teleport Edo Madaras massive attacks away from himself, other than that he has the speed and intelligence to face Edo Madara)
Naruto in perfect Kyuubi mode (His TBB can more than deal with Edo Madaras landscape wrecking attacks, it would also be a very fast process teaching naruto how to seal, like a 3 month job tops, he is an uzumaki for goodness sake how can he not even know how to seal, embarrassing. He also has more life energy than minato since he is part uzumaki)
Naruto Kyuubi Sage mode ( Without a doubt would destroy Edo madara, and half the ninja world)