The person at the service desk at Copenhagen Airport Sixt rental, Sebastian, was very friendly and helpful. The fact that we weren't offered the choice of automatic and manual on Kayak's website, kind of created a bit of confusion when picking up the car. But he was able to take care of everything, but at a higher rate. So anybody renting on a 3rd party website should be careful. However, the worst experience was when returning the car, they charged me for a damage that was there already. I had taken a photo/video when picking up the car like Sebastian suggested, but after 2-3 weeks of waiting for a response to the complain I had lodged with customer service, I received no response. Renter beware, be sure to document the damage and probably bring it up at the service desk. No one accompanied us to get the car, so we weren't able to show that there was prior damage to the car already.