The 500GB Iomega StorCenter was only unit I tested that supports Linux clients. It also supports disk mirroring, which can help ensure business continuity for small office environments. In the mirrored configuration, the cost per gigabyte for the $439.95 device is about twice that of a single, 250GB shared disk. Still, that's not a lot to pay if you need fault-tolerant storage. Mirroring has another benefit: like most shared storage devices, the StorCenter saves file version histories when backing up. If it fails, you lose access to your file version histories. Mirroring helps preserve that data.

With a street price of about $200, the 320GB Buffalo LinkStation is aggressively priced and has the most sophisticated security configuration options for small office environments. It doesn't include a print server function though, nor media streaming support.

If you want media streaming, the Maxtor Shared Storage II supports UPnP, as does the StorCenter, but the latter uses an older-style, parallel ATA disk interface rather than the newer, faster serial ATA in the Maxtor unit. The Shared Storage II was also the only unit I tested that doesn't support older, Windows 98 machines.

The Western Digital NetCenter model I tested shows how tempting it can be to upgrade to a larger drive. The 500GB NetCenter has a list price of $399.99 but street prices are around $275 -- that's just $75 more than what the 320GB Buffalo model sells for online.

Because I want to store shared data on the network storage device and maintain data on local PC and Mac machines as well, the capability to do bidirectional backups is important. Both the Iomega StorCenter and Western Digital NetCenter, with EMC Retrospect Express, met that requirement. Client licenses to back up all of my workstations, however, will require a $49 upgrade to Restrospect Professional 7.5 (the regular cost if you're not upgrading is $119). That covers three client licenses. I'll need two more, at $37 each.