I just booked a rental car online. With possible exception of Alamo, all of the online reservation systems for the major rental car companies suck. All of the systems more or less worked, but they were all slow, clunky, and had major usability issues.
Avis was the worst of the bunch. I typed their URL into my browser and got the following message: "Your session has timed out for security purposes. Please click on any link to restart." My session? I've never been to your site before. And click on any link? Well, the most prominent one is that stupid DoubleClick banner ad, would you like me to click on that one? Oops, I'm off somewhere else. Come on Avis, I just want to rent a car...I could care less about your stupid sessions.