Heavy, aerodynamic vehicles tend to get much better mileage on the highway than the city, that throws things off when we compare.
I believe our 300C will get 31 mpg easily on a long flat trip at, say, 65 mph. No problem at all. However, driving 1 mile to school and back in the morning and afternoon, starting on cold days, you're looking at 12-14 mpg. I would do better driving my Valiant.
The same applies to our minivan, though being a 2006 3.8, its highway mileage tops out at around 26 on a good day, yes, that's freeway-only. The six speed really helps, and the 4.0 and 3.3 both got much better mileage than the 3.8. Oops.
Well, the plan is that eventually the minivan will be replaced by a Patriot, but dang, the seats in the new Compass were just incredible, I wonder if Patriot will get those? If so, I might spring for a _new_ Patriot. Though if I had my way, I'd get a Fiat 500 ... stick.