I have to say, I've been running my own mail server without a single problem for years. OK, the way I do it is a stretch of the definition of "running my own web server" but I have full control.

What do I do?

Get a nice VPS from a company like GoDaddy. Setup whatever domains you need. Setup as many email accounts as needed. And off you go. No problem. I don't even have to think about email.

I thought about rolling my own on one of our Linode servers but every time I compare the no-brainer of doing the above to what it would take to run this ourselves on Linodes I can't justify the pain and aggravation.

What I don't like about the Gmail approach (other than it is Gmail and I do not trust Google to not shut down all of our accounts for some stupid reason) is the cost. I can spend a few bucks a month on a VPS and have a hundred email addresses. The same on Gmail would cost significantly more and you would be under their irrational thumb.

A few years ago I looked into running Zimbra on Linode. Back then it was so resource hungry it just didn't make any sense. I wonder if it has gotten any better over time? I really like the concept.