I've had my 2014 SS Sedan now for a little over 2 weeks. I traded in an automatic 2011 SS Camaro convertible.
I do a lot of city driving and have not seen much difference between the MPG of the cars. ~16.5mpg
I feel that the SS sedan has a smoother acceleration curve then the SS Camaro.
The SS sedan has plenty of interior space too. I had 4 passengers easily in the car this past week.
I am quite happy with the SS Sedan