I'm using Locus Pro on Android - I don't think it's using OSM data exclusively, yet I wouldn't go back to Google Maps: the ability to have truly offline, vector

I'm using Locus Pro on Android - I don't think it's using OSM data exclusively, yet I wouldn't go back to Google Maps: the ability to have truly offline, vector maps (not "eh, just cache these few tiles, that should be enough") and track recording are the killer features for me.