I would be very weary in using U-Save as they really push you on getting their insurance, which jacks up the cost of the car another $35.00 a day and the cars they have are older and not reliable. You are more-or less stuck using Hertz, which is very expensive as they are they only other option at the airport.
I tried enterprise which is 5 minutes from the airport, but they do not come to the airport as the airport does not allow them, so you would need to take a taxi to there location. One problem with Enterprise is that you cannot drop off the vehicle anywhere else other then back to them. So although you may save a few hundred dollars with Direct Air Flight price, by the time you add the extra fee for bags and paying double for your car rental, your savings is really not that much.