This guide is really good as it goes almost whole mile. It also does very good if not excellent job at illustrating how hard it is to set up, secure, and maint

This guide is really good as it goes almost whole mile. It also does very good if not excellent job at illustrating how hard it is to set up, secure, and maintain your own email service. There are lot of places to go from here, including multiple MX'es, backup/recovery, etc. Nevertheless. I've been using my own email infrastructure for almost ten years years. For last four I'm totally over it. Yes, there are some things to do if you absolutely want to be free to chose your email provider whenever you want to - having clear choice where to go, having backup off service provider, having migration strategy in place, etc.