I think it still has the same distractions as talking on a regular phone, because you're still talking and your mind is thinking about something else, besides driving. I think people should just deal with not talking on their phone when their driving, even through Sync.
As for the music capabilities, it sounds useful, but what if you don't know a specific song you want to listen to? Do they have a shuffle function through your voice? If they do, that's pretty awesome...