I've been checking out his videos for the last 2 days on youtube. Just do a search for 'Matt Stone 180'. He's dedicated, highly informed and passionate and definitely 180 from Paleo. His basic message 'rings true' to me, both logically and from experience. Doesn't mean I'm 'going there' though.
As another poster wrote, he's 'been there, done that' with a lot more stuff in the health arena than most (including paleo). That alone gives him a lot of cred with me.
Lastly, it's probably a good idea for anyone before 'fully committing' to paleo at least give contrarian views a listen.