The ability to set up an email account for our organization in just about one day, that was previously impossible due to security concerns! I am able to use my own domain instead of having all emails sent through Exchange or Gmail accounts (which are not secure). This has made life easier because we no longer have issues receiving mail from people outside work who don't want us knowing they're sending personal correspondence using corporate resources - now everything goes straight into Outlook without any hassle at home/office end!!