I haven't found a better program than Hertz. I'm also PS and will never go back to Avis for my business rentals.

If you rent at least 10 times per year, you can earn "5 Star" status. That basically provides a 1 class upgrade if availble. In addition, you'll earn a free day coupon after every (I think) 15 rentals.

After 40 rentals in a calendar year, you can get to "Presidents Circle" status. That's when things start getting interesting.

As a PC, your guaranteed at least a 1 class upgrade. Often I've received several class upgrades. In Houston, I would rent a Midsize and very often (every week for 8+ weeks in a row) get a Infiniti G35. After adding the G35 to my profile, I also get it on weekends in LAX, ORD, and PHL.

Last fall, in Honolulu we reserved a full size and got a Caddilac Deville using a free day coupon. In IAD, reserved Full received a Lincoln Towncar ultimate, on a free weekend coupon.

I've never failed to receive at least a 1 class upgrade, and usually get a several class upgrade. Though sometimes they go too far and upgrade me into a gigantic boat, like the Grand Marquis that I don't like. Usually I can go in and ask for a downgrade to something more normal.

In addition, the selection of high end cars at some Hertz locations is really great. Jaguars (X-Type, S-Type, XJ8, XK8 convertible), Caddilac Escalade, Land Rover Discovery, Infiniti G35 FX35 Q45, Volvos, Lincoln, Audi A6, Hummer H2, plus usual cars like the Mazda 3/6, Toyota Solara Camry Avalon, Nissan Altima Maxima, Kia Amanti, Subaru Outback... etc.

I select Hertz ZE1 points instead of airline miles or hotel points (1pt / $1, 25% bonus for PC level members). For our vacation this fall we're getting a Jaguar S-Type, XK8 or Lincoln Navigator for a week using 5,000 points. I think that's a great deal. We would never pay the $800 weekly rate for one of these cars.

I'm willing to drive an occasional Taurus or Grand Marquis to get a fabulous car using points for our vacations.

I believe National may give you free rental days much faster than Hertz, but no other program has been as consistently good for me.