I perceive the main benefit to the NAS hardware to be ease-of-management in terms of RAID via a software stack, and of course, physical hardware slots for holdi

I perceive the main benefit to the NAS hardware to be ease-of-management in terms of RAID via a software stack, and of course, physical hardware slots for holding lots of disks. You can easily build a NAS with pure Linux/FreeBSD and a case with disks inside.