I downloaded this before a trip to Oslo, Norway. I wasnt expecting much, especially when I found T-Mobile limited my overseas roaming experience to 2G! But the app blew me away!
Firstly it functioned perfectly, even on the restricted bandwidth. Its location GPS was very accurate on my previously downloaded map. Within a day I was not only walking around the city, but using the tram system, as all the lines were clearly marked. It even told me the times of the next trams at any station. Looking up any address or sight was easy, and it would immediately tell me how far away it was and how to get there. Not only that, it remembered a number of prior locations (ideal when trying to get back to the hotel after a heavy days sightseeing). The accuracy of the GPS was a life-saver when trying to get to commuter train stations with unpronounceable names in the suburbs to meet friends!
I have used any number of maps while traveling, but this is hands down the winner IMHO.