As you may already be aware, we who work on Matomo (Piwik) believe strongly in owning the data you collect. Your data is your future, and we believe that should be in no one’s hands but your own. This is the reason we created Matomo. But we don’t just believe in owning your data, we believe it should be easy to own your data.
UPDATE 2019 August: we have released Google Analytics data importer that will help you seamlessly transition from Google Analytics, a proprietary analytics solution to your own private Matomo installation.