I have an Avis Presidents Club card and am Hertz Platinum as well. I always use Hertz and find the Platinum service to be excellent - for example, I have not set foot on a rental bus in 5 years - they bring the car to the curb and dive you back to the terminal in your car when you return.

However, I have never used the Avis Presidents club service and would like to learn a little more since many people in the company seem to really like Avis.