While Obito may get a lot of hate, no one can deny that he is a fairly well developed villain. I am NOT saying his reasons are the best. But what he has done as a villain is far better than most antagonists in the series.
The dawn of Tobi, and the start of Obito's life as a villain came after being locked away in a cave with Madara Uchiha and Zetsu clones. Obito's whole dream while in this cave was to be reunited with his teammates, his best friend and love. And just sitting in a cave, forced to heal and slowly train over time was murder to him.
Just imagine his reaction when he discovered that Kakashi and Rin were in danger? He leapt out of the cave, hoping to help them as fast as possible. Injurying himself to try and get out of the cave, I believe. He rushed to the scene of the attack and was shocked to discover a dead Rin with Kakashi's hand through her chest. He went mad and killed the entire enemy troop. After months of only wanting to be with his friends again, he comes back to seeing the love of his young life dead. By the hands of the comrade who he "died" to protect and swore to save her no matter what. He would feel utterly defeated. Not to mention he later learned that Rin would die no matter what. The Sanabi was bound to break out. There was no saving Rin, it seemed. He did go insane here and. . The flip of the coin decision that caused him to attack Konoha and his sensei was random.
I did not enjoy it, and I despised the fact that over Rin, he attacked a village filled with friendly enough faces. Not to mention he later killed his clan, and didn't seem to mind it. His tail spin into chaos was far too.. spontaneous and without good enough reasons. I would have liked a more "built up" reason for being evil.
But, as "Tobi" he has got to be one of the best villains we've seen. "Tobi" was the mysterious and dark figure, lurking behind Pein. Before we learned the secrets of Pein, "Tobi" was ordering him around and STILL acting casual and like a goof ball.
His deceit the entire series as "Tobi" was fantastic. The way he was playing with Sasuke, Naruto, Kakashi. When he confronted and revealed the truth of Itachi to Team 7, I felt as if "Tobi" was doing this to try and make Naruto realize Naruto was never redeeming Sasuke. That he's in too deep, and Nagato's redemption was a fluke. He was always that shady guy, possibly Madara himself, watching things unfold.
He was the man who had plotted for his entire life for this, and was finally taking action. FINALLY doing things. His peak as a villain for me atleast, was the battle against Konan. He was at his prime then. His words, his actions, his speech. The fact he used Izanagi. . And then the confrontation with Nagato's corpse where he let loose a few angered words.
I loved it. During the war, he was great UP until a few chapters before the reveal. The calm, masked figure was losing his cool and the "Obito" personality was coming out. And, while it is getting better, Obito is a bit too whinny for people to like. He lacks that edge he once had.
He's in the top three villains, in my opinion. (Pein, Obito, Orochimaru).