Very poor service. Both when I was renting and when I was returning the vehicle I had to wait a very long time and the driver for the shuttle was very rude.
The car was in poor condition, the low tire pressure light was on the whole time, even after filling the tires (which were very low when I was given the car), it smelled of smoke and there were ashes in the cup holders.
I would suggest just paying the extra and getting an on airport rental.