I use both . Facebook is more easy to use. Orkut needs to be revamped by google. The New social site by google known as google+ is not attractive either as more than Half of the internet users are hooked on with Facebook.
Orkut was good before as it was the only social networking website which most people knew about. But now with so many different options available to the internet consumer they have many options to choose from and among them all Facebook is the most preferred so facebook is best as compair orkut