As others have alluded to, these are really two different types of cars for slightly different purposes. If I needed 4 doors and could stomach the looks, I'd go for the charger. There really isn't another sedan, offering that kind of grunt, in the 40-48K price range, it's a good bargain.
I think the new Charger front end looks ok, but the sides and rear are still a bit visually awkward to my eye. If you don't need 4 doors, Mustang all the way.