The Seagate BlackArmor NAS 400/420/440 is a heavy duty file server and backup utility. I’ve implemented this in one of my client’s business and it is doing the job well. My administering of the device was for the purpose of serving files to a multitude of computers that consisted of systems running Windows XP, Windows 7, and Mac OS X. I primarily selected this NAS because of its heavy duty look and capabilities. It comes with a large cooling fan and dual Gigabit LAN interfaces that can be aggregated into a two Gigabit interface. The second LAN interface also serves as a backup in case one the interface goes down.
There were some difficulties with the device in terms of making it compatible with Windows XP. Errors were a major issue that consisted of having “Network source not found” messages come up during file transfers. This problem was mitigated by updating Windows XP with the latest patches, but it did not completely stop the problem. The device works perfectly with Windows 7 and Mac OS X though. Another issue is of recovering your files should the device controller go bad because mounting in Linux with the LVM2 file-system isn’t that easy, so recovery can be an issue.
Bottom-line: The Seagate BlackArmor 400 series is dutiful with good capabilities for redundancy, but watch out for potential error messages when using with Windows XP.