I am now using CalDAV to sync my phone to my Google Calendar. Previously, I had no application to sync my calendar with. Subsequently, when I restored my phone as a new phone (given directions to do so by Apple for a battery issue I was having), I lost all of my hundreds of past-present-future calendar appointments. So I decided to setup Google Calendar and CalDAV. I set it to manual syncing, so only when I open the Calendar app (why would I sync it every 30 minutes?). It's amazing. Little drain on the battery and a great way for me to keep up with my appointments. Anyone else use CalDAV? Exchange users can leave now.