I have a 05 LLBean Wagon and average 20.8 driving mixed back roads and urban and in-town about 18. Haven't had a highway trip to compare. I have managed an extra 0.5 mpg shifting manually with the upshift at when the light comes on. But I get bored on a 55 mile commute and it gives me something else to do.
Better gas mileage would have been nice and with regular fuel, but I needed something with enough power to comfortably tow a sailplane and trailer and make it up a mountain.
Other than that, the car is comfortable and drives well. It is not the same as the MB 230K I had before, but it isn't close to being the same thing to compare.
Chip F