Not a good interview performance by Harris. You can tell from the edits that they backed up and gave him a clear chance to articulate his thoughts, and he seemed to struggle even then.
I think the real value of his book, and others that will follow, is that it provides an alternative to point to when the assertion is made that religion alone is the source for morality. He may not make a bullet-proof argument, but it does at least chip away at the final pillar upon which religion is staking its claim to legitimacy.