Summary: I am only giving this three stars initially because it's new and, as with so many things, its real value will only be determined over the long haul (I'm quite tired of replacing failed drives). I spent a little more on this model because it supposedly is designed specifically for use in NAS (like my iomega ix2-200). Hopefully this means it will last longer in a higher-vibration environment (two of them mounted side by side). Time will tell.
Summary: I bought the ST NAS 2T and the WD RED 2T to be used for a ZFS filesystem in a mirror configuration. I use this box for windows backups (over Samba) and media storage - a light NAS workload. The hardware is old so I'm only running the drives at SATA 2 not SATA 3. Under light load both drives work like champs. Under read conditions both drives work like champs. Heavy writes are a different matter.
Summary: The drive arrived wrapped in anti-static wrap, loose in an oversized box. Frankly, I'm surprised it even worked considering how it was packaged. Even with it working, there is no way that was good for the life of the drive. Overall comment. In the past two years I've burn't through 3 of 4 Western Digital 1TB SATA drives on my Buffalo Storage (NAS) server. In addition I had a network DVR with 8 drives, all originally Western Digital. Of those, 3 failed as well.