I've been reserving online and making the most of double points that way. I don't believe that any of the other car rental agencies are that generous with their points/freebies.

Sure, I can "have my name in lights" with Hertz, but their newly rolled-out program is a joke - rent 40 times and get a free day! or something to that effect. I believe that Avis has a 10 rental/1 free day program or something equally cheap.

Since I usually rent for a week at a time, I'll gladly take the 500-600 points for that rental which gets me a free day or a good part of the way to a vacation package over a free upgrade. Besides, I have been having terrific luck getting unexpected upgrades with Budget. In probably around 2/3 of my rentals I get anything from a mid-to-full bump up to a convertible/SUV.