I had a brand new 1.4t Jetta as a rental for a few days and I was blown away with the fuel economy. I was driving it under the most ideal conditions (80-100km/h) on country back roads, so this was obviously a massive advantage. I didn't get a chance to drive a full tank, but for the 439km I did the car only took 24.23 liters, so hand calculated that comes out to 5.5l/100km (43mpg). This was inline with the MFD display as well. Realistically I know that a tdi like the 1.6 they sell in Europe would get a much lower fuel consumption, but it's still rather impressive.