Most people think Prius is only good for city driving, the fact is that Prius is also very good in highway driving. In 65MPH (>100KM/hour) highway driving, I can get more than 45 MPG (~20KM/L)
For the gas consumption of Prius, you can choose to believe a 200KM test result in a car magzine, or to check the detail gas consumption of Prius owner who had more than 100000 miles driving (>160000 KM) .
How do you know the cost of maintenance for Prius is higher than the regular car ? Actually, it only needes oil change and tire rotation every 5000 miles (8000KM).
The detail cost of maintenance for Prius in John's Prius. In addition, you can find very detail gas consumption data also (>160000KM long term data)