Opinions:
Google Calendar Sync allows you to sync events between Google Calendar and Microsoft Outlook Calendar.
Staying on top of your Google Calendar and Microsoft Outlook Calendar events has never been easier! You'll be able to determine the direction of information flow, as well as the sync frequency. Keep in mind that it's not possible to sync events on secondary calendars at this time. Google Calendar Sync will only sync events from your primary Google Calendar and your default Microsoft Outlook calendar.