I went with zfs on Debian over unraid, freenas, or omv for my current server. This way I have full control and updates for the system with out nasty surprises later that they changed some standard way of running a service or library. I've used QNAP with optware/entware then lenovoemc and never again.

It's a lot easier to learn to set up smbd, NFS, nginx than deal with kludged together solutions later.