I'd go Benson for sure. He has been a steady and consistent producer this year. He has yet to put up a really big game, but he has put up decent numbers each week.
Fred Davis I like, but he has yet to find the end zone this year, and I just cannot see flexing a TE when you have a good play at RB.
RB is usually a much safer bet than TE, and although the PPR benefits the TE a bit, you can be much more certain that the RB will get the touches. My opinion: Go with Benson.
QB: R Griffin III, A Luck
RB: A Foster, F Gore, T Richardson, K Hunter, M Hardesty, A Green
WR: V Cruz, M Austin, P Garcon, S Moss, B Hartline
TE: J Witten
K: Matt Bryant