madara drops a meteor and kills everyone
Deidara blows it up. The clay artist could be very useful in this fight, since he's one of the only ones who can counter Madara's large scale attacks.
Meteor? Meet C3 bomb.
Akatsuki has a half-decent shot here. Together they're an extremely versatile team, they have the brains of Itachi, the battle experience of Kakuzu and have enough power and hax to make what the 5 kages brought to the table look like a joke.
I would have said Madara definitely wins, but when you add in Obito, things get a lot trickier. The Uchiha grandaddy is going to have to watch his back for the entire fight, because if not, he's getting dumped in the kamui dimension. Obito can avoid almost anything that Madara dishes out as well.
But once Madara brings out PS, most of the team become useless. Konan's only use in this fight would be to obscure Madara's vision with paper (but the sharingan might negate that anyway, so meh). Black Zetsu could manipulate the earth at its feet, but I don't see how he could put it down. Chibaku tensei might stall it, but again, wouldn't end it. Deidara could prep C0 while this happens, which might be able to break through PS or even destroy it. After that, Obito (who is the only one who will survive the blast) can kamui him.
If even C0 can't get through though, then it's only a matter of time before they're overwhelmed.