The are not real comparisons with Gmail with is a web-based client, an email server and a managed service.

On this list, I believe at only Zimbra provides all of these options, but the article really only looks at the client.

Having run my own email server for about 10 years (1996-2006), I eventually gave up due to the huge amount of work it took to stay secure, current with email server "policy" and deal with spam.

I have always either run my own server or paid for the service. I have never used Gmail beyond a use as a testing and backup email account.