You gotta be kidding.
Vito was of course the best Boss.
He was not only good and strong leader
but he was also a very good man.
He was kind and warm hearted and he really cared about his family. Both his family and his "family".
He was a good old grandpapa, you just gotta like the man.
But also a man of justice. You would love him if you where his friend and fear him if you where his enemy.
You can ask this question in another way:
"If you had to be a mafia soldier, who would you prefer to work for?" Don Vito Corlenoe, of course.
The only true Godfather.