Are we talking about go or no gi? I think nogi, there is no one who is going to walk through either guy. I actually don't see it ending in submission, both are so wily. If I gave an edge to Penn, it would only be based on physical talent - not saying that Eddie is not physically talented, but Penn is ridiculous with his natural balance and flexibility. Eddie had to work for it.
If we are talking gi, you have to give BJ the advantage. He won worlds in the gi, and Eddie doesn't spend very much time in the gi (from what I know, not positive though). Then again, I wouldn't be surprised at all of Eddie caught him.