Pietrangelo side for me by a wide margin, don't even need to put any emphasis on what else your getting in return, which I feel isn't even bad.

Your getting an elite player, and your not moving any such thing in exchange for said elite player. Sure Strome is a nice piece and Marchand is a good roster player, but there very much expendable when picking up an elite player like Petrangelo. The fact that it really bolsters your D is just extra incentive.