I really hope this functionality gets added to Google Maps. I've never used Waze but the features sound awesome for phone-based GPS and navigation. Google Maps are already very accurate and adding the data-sharing features from Waze would provide better traffic data, more accurate travel times, and a whole host of added benefits for Google Maps.
I've been using this app since last year. Im living in a country which I dont know much. This app helped me reach places without having to spend a cent on data network. I just choose the destiny before I leave home, using my wifi and then it downloads everything related to that location. The voice and NFS-like OCR is just amazing.
This is the best offline GPS app I've ever used. And that is something Maps does not have.