Having seen both "up close and personal"
the Challenger is a bigger car. It's built of a shortened 300C chassis.
From what I've gathered, it'll be offered in limited numbers, with the 6.2L Hemi. If you're looking for a "muscle car" with seating for four, the Challenger is your car.
It's a nice looking car.
IMO though, the new Camaro's styling is better.
(A funny "incident" at last years NYIAS. I walked over to look at the Challenger, and the guy working on the Challenger for Dodge commented how much he liked the new Camaro, and that he owns an SS himself!
)