[lzhou]

For an API, you can also try http://open.mapquestapi.com/nominatim/ (which is kinda free -- and uses OpenStreetMap data).

The biggest problem we've had is changing non well-formed addresses / ambiguous addresses into canonical addresses with lat/lng. Google Maps wins on that front.

[thecodemonkey]

We obviously can't beat Google in that case :) That's also why it's priced to be way more affordable. It does however happen that Geocodio is more accurate than Google Maps - try for example "8895 Highway 29 South, 30646" (Address of a CVS store) on Google Maps and Geocodio.

[me_bx]

I'm using mapQuest geocoding API[1] which basically does what you do for free, without the rate limits.

setting it up was quite a pain because they don't use semantic http codes, and I had to play with it a lot to handle their undocumented error codes (they store it inside body.info.statuscode). Good to read that you return semantic http codes.

If you want to differentiate from the competition, I would suggest that you improve the address parsing and support more patterns. Think of us having to geocode user-typed location fields from twitter. Enjoy it :)

[1]: http://open.mapquestapi.com/geocoding/

[pkh80]

Cherry picking one example does not make you more accurate than Google Maps. TIGER has some giant holes in it, and is based on block faces not building footprints like Google Maps. In most cases Google Maps will be much more accurate and comprehensive.