If you have already plunked down $500 for a Drobo and have other PCs on your network that you'd also like to backup to your Drobo, the $200 DroboShare companion piece is a no-brainer. It's near perfect for small offices in need of a dead simple backup solution, but home users eyeing the pair at a combined $700 may find themselves drifting to a less elegant but cheaper and feature-rich network attached storage setup. Whether you think $700 is too much to pay for an empty, four-bay networked backup drive depends, I suppose, on your view of network configuration settings. DroboShare makes it completely pain free to set up a shared drive across your network, which to many will be worth its weight in gold, but there are cheaper NAS/RAID drives such as the D-Link DNS-323 and the Iomega StorCenter Network Hard Drive that let you do more.
DroboShare is designed to fit directly under the Drobo. It's the same width and length as the Drobo, and it has four depressions on its top that line up with the Drobo's four rubber feet so the two units can be docked securely.
DroboShare ships with three cables: Ethernet, USB, and a Y power adapter. On the back of the DroboShare unit you'll find four ports: Ethernet, two USB, and power. You simply connect one end of the Ethernet cable to the back of the DroboShare and the other end to your router, and then connect use the short USB cable to connect the DroboShare to the Drobo. (The second USB port on the DroboShare lets you connect a second Drobo should you outgrow one.) Finally, connect the Y power cord to both the Drobo and the DroboShare and then to the end of the Drobo's power cord--it's convenient that the DroboShare doesn't require a second outlet.
One drawback of this setup is that connecting the Drobo and the DroboShare via USB limits your bandwidth to 480Mbps of the USB 2.0 spec--a potential bottleneck for Gigabit Ethernet networks. We tested the DroboShare via a 100Mbps Ethernet router, however, and the USB connection was not a speed trap. We transferred 2.1GB of video files to the Drobo via DroboShare and it took 6 minutes 42 seconds, for a throughput of 42Mbps. Transferring that same data via a direct USB 2.0 connection to the Drobo took only 1 minute 58 seconds, for a throughput of 142Mbps. In another test, it took 66 minutes to write 16.4GB worth of photos via DroboShare, for a throughput of 34Mbps.
One of the more convenient features of DroboShare is that it lets you switch from a networked Ethernet connection to a direct USB connection on the fly--NAS to DAS, as it were. Our Windows XP and Vista machines recognized Drobo instantly, whether connected via Ethernet though DroboShare or directly to Drobo via USB without needing to install the Drobo Dashboard.