Outputting the changes between syncs has been requested by several clients recently. There's not an easy way to do it other than enumerate the change set.
We have added a Method called GetChangeSetSerializer() on the compareResult this can be used to write the ChangeSet to an XML File.
i.e.
public override void AfterCompare(ProjectAutomationCompareResult compareResult) { if(compareResult.HasChanges) { compareResult.GetChangeSetSerializer().WriteXml("AllChanges.xml"); } }