I looked at Freenas and I was absolutely not a fan of it for several reasons:
- ECC significant memory requirements due to ZFS
- Jail systems to isolate processes
Openmediavault is a very nice distribution made by Volker Thiele (former Freenas) based on Debian.
The distribution has evolved significantly since the beta version and is now available in version 4.
I use it as a virtual machine through Vmware ESXI, and passthrough of the hard drives.