With AAA or many other affinity discounts, I have generally found Hertz as cheap or cheaper than the other major rental car companies. I have also had good experience with National. Once in awhile I enjoy playing the pick-a-car game with the National Emerald Aisle, but generally I like knowing what I'm renting and go with Hertz. The Hertz NeverLost system is a outdated and a pain to use.

National often provides better rates for one way rentals, and if you rent locally often, the partnershp between National and Enterprise can be beneficial.

Avis cars often aren't cleaned as well, but I got a much better rate with Avis on an European rental. YMMV considerably.