Choosing a large company was definitely the right call. Initially, I was worried about various upsell services like insurance, based on online reviews. We were very cautious and asked many questions when reviewing the contract during pickup, but there were no hidden charges. All terms were clearly stated in the contract, such as a diesel surcharge of 3.57 euros per liter if the tank is not full upon return (which is very expensive, so make sure to return it full). The service was excellent. They held the car for us for half an hour past our scheduled time without charge and calculated the rental period based on our actual arrival time. We were also a few minutes late returning the car, but they didn’t charge us for overtime (which worried us for a long time, very touching indeed).