I have always used Arillas cars and I wouldn't want to change. The cars are safe and well maintained. You pay no extras and you are dealing with a honest, local family. I have never had a problem after twelve years of hiring cars from them. I once had a car that had a flat battery, and after a quick phone call I was given a replacement car whilst the battery problem was solved.
One big problem with car hire is how you much fuel you need to leave in the car on return. This is never a problem with Arillas cars.
One last thing, I love to think that I am driving around Corfu with the word "Arillas" on the car. I know it's a bit crazy but it's the same feeling I get when I am drinking Corfu beer, it makes me feel that I am giving something back to my favourite place.