I don't recommend hosting your own. I briefly had OSX server running a mail server for my small team. I quickly realized how spoiled I was by Gmail. Basic mail

I don't recommend hosting your own. I briefly had OSX server running a mail server for my small team. I quickly realized how spoiled I was by Gmail. Basic mail server setup was easy enough. But, managing things like out of office auto responders, server based mail filters, password resets, etc all required my attention. IMAP doesn't handle those tasks, and I'm not aware of a way for users to do those tasks themselves. I went back to Google for mail hosting, but will be investigating the other services below. (I'm still a free Google Apps user, so it's hard to move off of free).