OsmAnd nightly build (0.7.0 branch) is GPL'd, with offline vector OSM maps and it's mind-blowing. Navigation works, with voice. There is now a native rendering option on some devices, it's pretty spiffy. It can also record GPX tracks, with optional background service. The vector map of Croatia is 20 MB compressed, with a huge amount of POI data. Daily, an average of 50000 points are added to the map of Croatia. I've actually stopped using Google Maps, OSMAnd is the best map app and it's completely offline.