I would support this if it wasn't based on Ubuntu, especially 14.04. That is the last disto I'd trust as a secure mail server.
2. Their packaging team screws up packages regularly.
3. They have insane defaults of many package configurations.
4. They tend to do things their way rather than the standard way and come up with their own tools rather than using standard, well tested tooling / packages.
I could go on and on, but it's not a distro I'd ever let run on one of our servers, we used to run 100% Debian until CentOS 7 came out and in our eyes left it for dead when paired with the correct yum repos.