Very happy with Mailcow, it seems to be the best solution currently for a self hosted email server. It allows me to have perfectly authenticated email with DKMS, ARC, SPF and DMARC. I've set it up on an OVH vps and it's been running for a couple of weeks now.
In the past I have maintained by hand email servers, but - been there got the t-shirt. So I tested a few solutions such as Post.Io, iRedmail, etc. but settled on Mailcow as it is the most advanced and complete. Installation took only a few minutes.