With award mileage now based on the size of your car rental bill (or number of days rented), the Hertz program is clearly a better option for those renting for longer than a few days. Those renting for a day or two get more value out of Marriott points. Just to clarify a point made by rthib (above), Marriott points are NOT awarded by Hertz in addition to miles. You can get 500 Marriott points (for a corporate rental) OR the miles, not both. You can receive 150 additional Marriott points, regardless of whether you choose points or miles, if you stay at a Marriott in conjunction with your rental.