Re: It's still really hard to complain
You perhaps forgot wear and tear on the car?
If it really means something to me, I opt for the GSA rates (55-some cents a mile, covering gas, car maintenance and depreciation, etc.). Take an upcoming vacation of 1500 miles round trip. If rental + gas < $750 (my own car) then I'd rent. There are other variables at play for this particular trip, but you get the point.