Yeah, the nav option isn't even offered here in Canada on the Prius.
P.S. I haven't driven it longer to know for sure, but I'm starting to think the car will get lower gas mileage with my type of driving, in the winter.
The car seems to do as well or better with gas mileage in normal city driving after it warms up when compared to my 2001, despite the 2004 having much more power. However, it seems to take longer to warm up, which means more gas used for the warm up portion, and I do a lot of very short trips (under 15 minutes). Also, another negative is that rear windshield visibility is reduced somewhat because of the design of the hatchback.
On the plus side, the wind noise is reduced (0.26 drag coefficient), the sound system is much better (I got the JBL upgrade) even if it's a bit low on bass, the Smart Entry system is VERY cool, the tire noise is lower (more standard tires), and the ergonomics are better. The VSC definitely helps too - better control in wet snow (although part of that would be the tires).