First, the big perk of this external hard drive: out of the box, it's incredibly quick and easy to get going. The software pre-installed on the Ethernet Mini disk allows you to configure the basics quickly: just plug the drive into your USB port, run the software and configure an IP address. There's a web front end with a handy, if not very intuitive, interface to set up share points and accounts.
With that done, you'll have the basics up and running in just a few minutes. The disk comes formatted with a FAT32 file system, which means you can share files with PC users straight away, and importantly both parties can write to the disk.
If you're looking for an affordable office server, bear in mind that the Ethernet Mini disk houses only one hard disk, so you won't have any built-in redundancy to protect you from data loss. If your data is valuable - and whose isn't? - you'll need another backup solution.
Data transfer speeds are fairly good using the built-in USB 2 port. We wrote 1.3GB of data to the disk in 88 seconds and read it back in 83 seconds. This equates to a read speed of 16Mbps and a write speed of 15Mbps. It's not great compared to an internal IDE or SATA disk, reeling off at least 60Mbps.
However, network speeds are much worse. The same amount of data took seven minutes and 15 seconds to write to the disk - a speed of 3Mbps. Oddly, the read speed is exactly twice as bad at a whopping 14 minutes and 30 seconds, giving an atrocious 1.5Mbps. That's USB 1.1 speeds. At this rate it would take 47 hours to read the entire contents of this drive - let's hope you're not in a hurry...
While it's a great idea in theory, this device's network speeds are just too slow. It's only going to be useful for sharing small files, or being used as an external USB disk with a bit of file sharing on the side. You'd get much better performance from buying an extra internal drive and sharing it peer-to-peer.