RE: Surprise Surprise Surprise!!!!!
I can second what Roswell says.
The Mustang has a harsher ride then the Challenger. It may be due to the configuration of the suspension and size but overall the Challenger has a much better ride over rough road, highway and "normal" roads.
Seating comfort, well the Challenger being a larger interior guarentees more leg room and such with the seats being way more comfortable. The dash and console are cleaner and neater no feeling of things being condensed into smaller space. It is quieter as well and with the radio on you hear almost nothing from outside with the windows closed, not so with the Mustang.
It goes without saying the power on the Challenger is way better than the Mustang. Granted it is 425 hp Vs. 300 hp but still, the power to weight ratio should be a little closer but the Challenger is more a pure power monster than the Mustang.
Bottom line, buy what you like, makes you happy and satisfied. My wife wanted the Mustang and she got it. I wanted the Challenger and I got it. Shes happy, I am happy and that my friend, it what it is all about.