Non-violence is the greatest Dharma; So too is all righteous violence.
Another school of thought is a ruler should never think of his family. For him, his country is the supreme. But Ravana has not thought about his Lanka. His brother thought in that angel. So Vibhishana is the man who thought of saving his country.
But definitely, Rama's victory has become easy because of Vibhishana's support.
While, Vibhishan, since he was worshipper of Lord Ram from the beginning, and he always kept Ravan telling to not harm him, to not kidnap Sitaji, as if he did so, he will suffer bad defeat. So, Ravan asked him to leave him because he was constantly with Lord Ram. And so he helped him to defeat Ravan.
So, as per my views, both have their own significant roles here.
Do what inspires you !!
'Idhuvum Kadandhu Pogum "
Even this challenging situation would ease
Vibhisan on the other hand was a follower of Lord Rama and he did not like that his brother should fight with him. In fact Vibhisan requested Ravana to surrender to Lord Rama and return Sita and ask for forgiveness. Vibhisan was a great diplomat. He knew that Lord Rama being a divine person and fighting for justice and having support of so many monkeys and bears will ruin Lanka and Ravana may die soon. In the end all supporting Ravens will be dead or imprisoned. So best course is joining hands with Lord Rama.
So there is vast difference between the character of Ravana and Vibhisan. One is diplomat other is warrior. As far a kings quality Ravana is unparalleled but he died in his ego while Vibhisan got everything under shelter from Rama.
From human qualities point of view Vibhisan was better because he wanted to return Sita to Rama and then negotiate for ceasefire.
Knowledge is power.
Mother:- Like whom?
Daughter:- Like RAVAN
Mother:- What the hell are you saying? Are you out of your mind?
Daughter:- Why not Mom? He left all his Royalship &
Kingdom, all because his sister was disrespected.
Even after picking up his enemy's wife, he didn't ever touch her. Why wouldn't I want to have a brother like him?
What would I do with a brother like Ram who left his pregnant wife after listening to a "Dhobi" though his wife always stood by his side like a shadow? After giving "Agni Pareeksha" & suffering 14 years of exile.
Mom, you being a wife & sister to someone, until when will you keep on asking for a "RAM" as your son???
Mother was in tears.
Moral:- No one in the world is good or bad. Its just an interpretation about someone.