I use Google Maps on my cellphone quite a lot to get from place to place, espcially to audits. When I first started using cellphone navigation, it was GREAT! But in its current incarnation, it is not.
The mapping feature on my G1 (how many years ago?) was reliable and timely. Google Maps on my Samsung is usually slow, and often just gives up with its favorite message "GPS signal lost".
Fortunately today Mount Rainier was visible and provided enough orientation to get me home from Renton. Everyone should have such a handy volcano!