I have had some horrible experiences with Avis in Israel (avoid them like the plague), and so I tried to show some loyalty to Hertz recently when in the US.

I ordered a mid-size car with NeverLost in Arlington, VA for the next day via hertz.com. I showed up at the hotel location and the guy ran off the list of cars. No upgrades, but I went for the Mazda. As I was walking out, I asked to confirm it had the nav system. Nope. He went on to explain that just because I reserved the nav system, it doesn't mean I will get it. In fact, it didn't even show up on my reservation that he received. They also rarely have cars with nav systems, with most going to the airport. So I was told to be "thankful" I received a beat-up Pontiac that had a NeverLost. The NeverLost was horribly slow at finding its location, inaccurate when it did find it, and took nearly a full minute to recalculate a route.

The next week I reserved at Avis (also in Arlington). I showed up and asked if they had a Japanese car. They "only" had a Mistubishi Eclipse. Nav? Sure! Unlike Hertz, their nav systems are brand new Garmin Nuvis and can be put into whatever car you rent. Great nav system in a very fun car, and very good customer service.

I need a 1 month rental in January. Guess who I'm calling?