I'm posting these comments directly since others may find them more quickly this way.
On a recent trip to 3 countries in SE Asia, I wanted to load maps on my Android 4.0 mobile from WiFi (in hotels), then use them on the go without data service to help locate restaurants, public transportation terminals, or just navigation. I planned to get a SIM card in country.
So the issue, then, is what mobile app to use with what maps. If I were willing to pay for data service, then Google Maps would be the best choice, but I wanted offline use, and for the cities I would visit.
I tried several approaches (all of them interwork with the mobile's GPS):
1. The Google maps app for Android has a "use offline" feature that would be fine except that
the app responded with "unavailable for this location" for my cities.
2. There is an app called OSM: Open Source Maps Automated Navigation Directions (OSMAnd). I found OSM to be a bit complicated to join and use. Eventually, I installed the app,
but the map of Bangkok was not very useful -- not detailed enough and not enough English.
3. I preloaded a Google map over WiFi and just left it in the Google Maps app cache.
This was almost useful, but one could never be sure the right neighborhoods had been loaded to the necessary level of detail.
4. The City Maps 2Go app supplied some 220 or so excellent city maps. It also used GPS.
Actually worked well for most larger cities in SE Asia, and one can download Wikitravel supporting information. CM2Go can also download additional info from WikiTravel.
5. Tripadvisor City Guides will provide maps and information for a more limited number of cities,
but its map of Bangkok was not as good as CM2Go, and restaurant locations often had inaccurate coordinates.
My experiences -- hope some find it useful.