After reading everyone's opinions, I think Madara would own them all. Now granted I'm kinda partial to Madara, but still be's a bad dude.
SO6P and his sons, had to atleast know how to fight wether they were ninjas or not. Cause the sons fought, their descendents have fought for generations. Madara and Hashirama being descendents of theirs. Also, in the fight with Hashirama that Madara lost where everyone just assumed (and you know what you do when you assume, make an ass out of you and me) Madara had died. Madara got some of Hashirama's DNA (cells), so I think that counts as a win. No he didn't win the fight but he still won.
Now as for Pein, yes he's got some awesome skills but he wouldn't have his eyes if Madara hadn't given them to him (well at least Tobi claims thats how he got them). So I think that Madara would in a sense own him.
Now for Tobi, who I personally like don't get me wrong. But I don't think he could do very much to Madara but piss him off. He does that transparency thing were solid objects, people and all can pass through him. But like someone said earlier it only lasts for 5 minutes, which was the problem when Tobi fought Konan. When Tobi saw Madara in the coffin that Kabuto had summoned of course he's scared. And here's where I'm not sure where everyone is, all Imma say is it effects the plan.