We rented a car through Priceline and ended up with a car from Hertz. The woman who checked us out was friendly and helpful. She gave us an upgrade for free to a Toyota Corolla. The checkout process was easy. One concern was the numerous scratches and scrapes on the car, but we were told that they don't worry about that. I hope that was true and that mysterious charges do not appear on my credit card for scratches that we did not cause. The maintenance of the car could have been better--the brake pads were in desperate need of replacement. We basically drove around for 2 days with a metal on metal screeching.
The last concern is their policy regarding damage from accidents. We were told that if you don't get their insurance, they do not deal with credit card insurance or other insurance companies. I did not pursue what this meant, but I guess they bill you directly and then you have to get your money from your insurance in case of an accident. It seems to me like a draconian and customer unfriendly policy. Luckily, we did not have any incidents that caused damage.