I would like to provide a counter to the bad reviews here, as I had an excellent experience with Sixt. I rented a car at the Madrid airport, which was originally slated to be a Volkswagen Golf wagon or equivalent. They upgraded it to an Opal minivan without extra charge. The car worked flawlessly and we drove it to Granada, Valencia and then to Barcelona. Although we were supposed to return it to the airport, I found an office at Rambla de Catalunya 74 and returned it the morning after the day we were supposed to return it and there was no extra charge. The woman behind the counter, Angela I think her name was, was very friendly and helpful. She reminded me that the car needed to be returned with a full fuel tank, and let me take the car back out to fill it. Then, the next day I got an email from Sixt letting me know that I had left a pair of glasses in the car. This saved me the large expense of replacing them. Excellent customer service! read more