I have a '12 Laredo 2WD with the 3.6 Pentastar. I'm OK with my mileage so far, averaging about 16.5 - 17mpg city on the winter blend of gas. I averaged 23+ mpg on two long interstate trips last summer, mostly running at 80+ mph.
This is a BIG improvement over my '02 TJ Wrangler with the 4.0 and 31" tires....where I average 11-13 mpg overall. I think I might have hit 16+ MPG once in 10 years....going downhill with a strong tail wind
I love having two Jeeps in my garage....the luxury road cruiser and the sporty convertible for sunny days!