They are both great American cars with rich histories. Pontiac brought us the first true musclecar with the GTO. Todays Ponchos carry on that great tradition as best they can in this super regulated atmosphere.
On the other hand Mopar has had many milestone cars also including the Hemi cars, which one can still own today. Chrysler is always on the leading edge with their styling, not afraid to throw something new and different out there ie, Prowler, Challenger, Magnum, 300, etc.
I would pick the big SRT Hemi Charger if I had a choice.