Restore: This option is used when restoring the backup file on the same or different computer only if the same version of Microsoft Outlook is used (example: Microsoft Outlook 2007 to Microsoft Outlook 2007).
Migrate: This option is used when restoring the backup file to different computers and it will also help you to migrate from one version of Microsoft Outlook to other (example: Microsoft Outlook 2003 to Microsoft Outlook 2007).