We purchased our ATS-4 after renting one on vacation. We really liked it and bought this car within 30 days of returning home. It's a Premium model with the 2.0L Turbo.
Best fuel mileage to date was a 200 mile trip to Madison, WI for Christmas. Mileage was 31.2 while driving 70 - 73 MPH on the Interstate and 60 - 65 MPH on Hwy 18.
Regular day in/day out mileage has been 26 - 27 MPH in combined driving. Very happy with the fuel mileage and the decision to buy this car.