I have used Centauro many times at Barcelona Airport and never had a problem with them.
I was picked up on time and the efficiency and friendliness of the office staff was excellent.
On returning the car we were a bit late due to an accident, and although they had new customers collecting cars they did a quick check of my car, give it the all clear and got us to the terminal to catch our flight.
My fuel deposit was returned the next day.