We rented a car in Ljubljana and had the same experience as Niklaus.
Long waiting times to get the car. They sold me an extra insurance where the excess drops to 0 €. At return they found a small damage under the car. I never parked bachwards and I'm sure it wasn't my damage. Nevertheless, they charged me 91.50 € as administration fee. If You rent a car there look closely as hell during pickup. They just want to find something to charge you. Very unprofessional!
Good experience, the car selection wasn't that wide (we needed an automatic), but otherwise I can't fault them.