In stark contrast, the car rental firms never hesiatate to add hefty charges if you take the car back even a few minutes late.

I agree you can be just unlucky sometimes. I collected a car from Richmond VA through Hertz a couple of weeks ago. The rental agent came out to the lot with us and asked us which we wanted, pointing out the newer cars and those with extras such as SAT NAV and digital radios for no extra charge. I really couldn't have asked for more.