A good car rental company, though communication in language is a bit challenging.

Pretty good.

The rental car counter at Belgrade Airport was very quiet, no waiting in line, and the staff was quite friendly.

A local rental company, everything went smoothly for both pickup and drop-off. When picking up the car, I noticed a scratch that was not recorded, so I immediately informed the staff. They assured me that it was fine since they had taken photos. If I was asked to pay for it when returning, I could just show them the photos. During the return, they didn't check the scratches, only inspected the area under the trunk. Overall, it was very smooth.