Niether.
Sora is too laid back, and Roxas I don't know enough about.
My favorite is Riku, because of everything he did. He may have chosen the darkness, but he did it to save kairi, he did everything, work with maleficent, accept ansem, everything for kairi. In the end of KH it was he who helped close the door to darkness and he who saves Roxas from the heartless. He may have been swallowed in darkness, but he came back and that makes him a stronger character than any other.
Sora is too laid back, and Roxas I don't know enough about.
My favorite is Riku, because of everything he did. He may have chosen the darkness, but he did it to save kairi, he did everything, work with maleficent, accept ansem, everything for kairi. In the end of KH it was he who helped close the door to darkness and he who saves Roxas from the heartless. He may have been swallowed in darkness, but he came back and that makes him a stronger character than any other.