Since Sunrise is going away please build the same functionality in to Outlook ASAP, including multiple calendars such as Google, quick entry iOS keyboard, etc, etc.
Till now my wife and I jointly used the Sunrise calendar in order to have an overview of aach others activity at all times. This calendar has worked very well for us.
Microsoft has recently bought this calendar. I expect this calenar to be integrated with Outlook. The present calendar is not good enough!