I've driven more than 3000 miles in the past month with my Droid in its car dock. After using it this much, I have a pretty good understanding of how it works and I wrote a review comparing it to the Magellan GPS I used for the previous 50k miles. I also threw in some tips that might help you better use Google Nav and the Droid while driving. I hope it helps... let me know what you think.
Google Navigation version 1 real life review Joel Kleppinger