Rogan sounds more believable but I suspect you'd get the same results sitting down at Audacity and cutting together an MP3. You just have better quality samples of him talking to people in a podcast setting.
It's an interesting demo but I'm not sure why I would want this to exist. It seems like technology which you could only abuse, either through the generation of podcast spam or through the production of fake audio. Podcasts are legion and are already cheap to make and based on open standards.