I have used rentalcars.com before in europe and have had an overall positive experience. However, their North and South American Services has been terrible.
Chile-2016. Rental car company offices were closed upon scheduled arrival. 10:00am on a Sunday, and were not scheduled to open for three days... If I had know this during my booking I would have looked elsewhere.
Mexico-2016. Visa's CDW (Collision Damage Waiver/Basic insurance) was not accepted by rental car company. Instead, to rent the car for a week the company Firefly would charge us $638/week for insurance... Beyond ludicrous pricing... For this price, we asked to see the car first. We were led to a nearly empty parking lot with one car remaining. The sales person said he was surprised how busy they were and that eh only had one car left (ours from our prepaid reservation). The car looks like it had driven through the trenches in World War I.... Scratched, dented, dinged, and any extruding appendages the car had initially had been ripped off as it most evidently had been birthed through a cinder block wall... good heavens... the imagery of that prose...
Needless to say i will not be renting with RentalCars.Com in North or South America.