Tobi (A.K.A Uchiha Madara) is not, and cannot, be Uchiha Obito. Obito died soon after he gave Kakashi his Sharingan.
Madara has mastered the Sharingan further than any other Uchiha before him and, by what it appears, he has become immortal: Attacks go through him, he teleports, has lived since before Konoha has even been created. Plus he's the Mastermind behind the Akatsuki.
As for the characters themselves, Obito annoyed me, yet i do believe his words and what he tried to get through to Kakashi.
Madara is an interesting character to say the least, helper in the slaying of the Uchiha Clan and absolute controller of the Kyuubi beast, there are truly very few, if any at all, that can beat him.