This feature called Email Integration helps to sync all the data between both the platform and in addition to that Vtiger helps in linking the documents processed into Google Drive which is easier to keep references. Calendar integration helps to sync on recent appointments and meetings and these are the most features which are useful Review collected by and hosted on G2.com.
One of the challenges is also Integration Complexity if there's any customization needed and if there are any sync issues we might delay sometimes. Support and maintenance also but support needs for almost all products hence not a big deal Review collected by and hosted on G2.com.