I don't think you can go wrong with either. But if i were chosing, I'd go for Clark. Manning has been impressive this year, and the Titans seem to be the type to power the ball into the endzone when they get close. But like I said before, either would be a good choice.
def clark. huge upside and peyton is liking him in the endzone. he's been thrown to in the redzone numerous times and the lack of catches haven't been his fault (awesome defense or overthrows).