I am a tourist, I booked for a BMW 3 series in December for 8 days. The gentleman couldn't speak much English but everything went smooth and I was upgraded to an audi a4 combi with navigation for free which came very useful. My train was late so I called and informed sixt to adjust my timing which they did promptly. I dropped off the car on Christmas and after couple of days they returned the deposit. No issues. Thanks sixt.