From what I've been hearing, he doesn't let his personal feelings intrude on his work. He seems to operate in a situational mode, based on who he's working for. If he were on the Supreme Court, he would be working for the American People, upholding the Constitution. If that's his agenda, I am all for it.
Let's face it, all the factions here are into special interests. They may claim they want him to be impartial, but what they really mean is "I want him to support my view on issue X." They are hoping for personal opinions, figuring that he will interpret the law based on them, either for or against their own interests. And Roberts has been telling them he will interpret the law based on law and legal precedent. I like to think he really means it. If he does, his personal beliefs become irrelevant.