CLGeocodeCompletionHandler only has one placemark entry

I would definitely suggest using Google Geocoding API - it is simply superior. I also argue, that you should not fear the usage limit for Google Geocoding APIs requests.

If you are developing mobile application, I suggest implementing client-side geocoding - that means, that every device queries directly Google API. As it is directly stated in Google's own documentation

geocoding limits are per user session, there is no risk that your application will reach a global limit as your userbase grows.

More info in geocoding strategies docs and geocoding docs.