A person I was traveling with booked Fox.
Horrible, HORRIBLE customer service. Sales rep tried to up sell absolutely EVERYTHING. She was rude, pushy, sarcastic and everything else someone in customer service shouldn't be. She gave us the wrong directions to where the Fox cars were, which was icing on the cake of her attitude.
Additionally, my colleague was charged for hours driven. So it's not really unlimited mileage.
Spend the extra cash to be treated with respect!