Tobi is portrayed as a very bumbly, goofy and carefree character - something similar to Uzumaki Naruto and Uchiha Obito. There's no denying that compared to the other members of the organization, he seems too easy-going; he isn't as serious as the others about their cause. His finer points is that he's the lighter half to a set of characters who are very serious and arrogent; and doesn't hesitate to show it. In a way, he's more humanistic than the other members, but it doesn't eclipse the fact that he's apart of a group that takes lives when they feel necessary.

He takes joy in the finer points of life; when Deidara begins to lecture him after the capture of the Sanabi, Tobi doesn't hesitate to fall asleep as his partner babbles. It's apart of his carefree nature. It doesn't matter what his group may say - he can only remain as himself. Tobi clearly follows his own path and that shows his carefree side. While some of his group may not truly like his personality, Kisame Hoshigaki appreciates his ability to brighten the gloomy organaization.

With that said, it's easy to see that he's a very bumbly and goofy character. He fails to catch Sasori's ring when he tosses it into the air and runs away comidically when the going gets tough against the Sanabi, but that's all apart of who he is. However, something changed and now he's no longer the fun loving man we all knew.

Since revealing himself as the legendary Uchiha Madara, his personality and speech have become almost the complete opposite of what it was before. Where as Tobi spoke very formally and and used a correct manner of speech, Tobi now speaks less formally and comes across as more serious and arrogant. Whether this is truly our beloved Tobi and he was merely acting is unknown - but no doubt more will be revealed as time passes.