There are various differences between Facebook Insights and Google Analytics.
Facebook Insights collects more information about the demographics of the browsers. Through this resource, you can get information about user activity on your pages and the number of followers. However, its drawback lies in the fact that its reports are restricted.
Where Google Analytics is concerned, its reports are wide-ranging and interactive. Nevertheless, it has context and content restrictions; they are dependent on how the tracking codes have been executed. Also, it rates higher in greater segmentation abilities as compared to Facebook Insights.