Salesforce offers built-in server-side synchronization of data with Microsoft Exchange. It is called Salesforce Lightning Sync. GrinMark GESync is a cloud-based server-side sync solution that plays on the same field but better. Let's look at the comparison tables.
|Sync Direction||E > CRM||E > CRM, CRM > E, E <> CRM|
|Category Mapping||n/a||Category <> Event Record Type|
|Recurring Events||n/a||E > CRM|
|Sync Deletions||n/a||E <> CRM|
|Sync Invitees||n/a||E <> CRM|
|Skip Old Events||n/a||E <> CRM|
Besides default options GrinMark GESync is also backed-up by a team of professionals who can customize the solution for virtually any needs.