I'm now trying to use OSMAnd wherever possible. If there's a location I can't use it to find, I'll revert to Google Maps (and click 'no' to the opt in nag). When home, I'll make sure to update OpenStreetMap to make their map more useful.

I'm convinced that open data is the better option. Certainly, I'm happy to volunteer my time and effort to contribute to things like OSM (and Wikipedia), but I'm loathe to part with my personal data for 'free' to a huge advertising behemoth.