I've had the car for 6 weeks. I drive 35 miles round trip to work every day, and have been averaging about 42MPG, including weekend driving around town.
I went on my first trip last weekend: 265 miles each way, over low mountains (Asheville, NC) and undulating roads (eastern TN and western NC). After 550 miles (~85% highway at 65-80 mph) and 15% city, the average MPG was 48.6 !!
I'm sure I could get wall over 50 mpg on a reasonably flat highway.