I've been looking a Zimbra [https://www.zimbra.com/] for a while. I like the general idea of the product. Even the free version is feature-filled. My only problem with it is that it seems to be a resource hog. You'd have to get a fairly fat Linode to run it.

I've used garden variety email hosting auto-magically setup on VPS's from such luminaries as GoDaddy without problems for many years. I have never worried about how to setup an email server, just get a cheap VPS, setup email addresses and you are good to go. Given this experience I have to admit to not understanding why Zimbra is so fat.