Initial setup is made easy thanks to the bundled NAS Navigator software, which will hunt out the Duo (and any other Buffalo NAS) on your network and give it a shortcut to both the device's web interface and to mapping its storage to a network drive. Another feature that could prove useful is the Auto power option. In this mode, the LinkStation sits idle until a PC with the Navigator software tells it to wake up. Although this isn't exactly useful when using non-PC devices or web access, obviously.
There are a number of features available on the LinkStation Duo that might incline you to leaving it fully powered all of the time. UPnP and DLNA compliant media streaming is one plus point, showing no problems using Media Centre on a Windows 7 PC, an Xbox 360 and a PlayStation 3 - as you would hope. If you use iTunes then the Duo's ability to operate as an iTunes Server will likely prove useful.
A built-in BitTorrent client should prove useful, too, letting you download all of those freely distributed files you're so keen on. Linux distributions, Nine Inch Nails' The Slip - that sort of thing. This is configured through its own separate interface, which is perfect for control with a smartphone - why turn on your computer just to start a download?
A USB port on the back of the Duo can serve a couple of functions, some controlled by the logically labelled 'Function' button found above it. The simplest of these is to connect an external hard drive to the Duo, which can then have data transferred to it either on a scheduled basis or when that Function button is pressed. Alternatively, that function button can initiate transfers from a USB storage device to the Duo. Oddly, only media files will be copied, though at least these are placed into appropriate folders. Usefully, this works for files on a digital camera or camcorder, too.
According to Buffalo, one of the major advantages of the Duo over its predecessor is a maximum transfer rate of 40MB/s - 166 per cent faster than before. As such you'll definitely want to be using a direct, Gigabit Ethernet connection as such swift transfers put my aging 85Mb/s HomePlug kit to shame.
Transferring a 3GB ZIP file of various MP3s to and from the LinkStation Duo returned a 37.2MB/s read and 22.3MB/s write speed, while that same assortment of files separately gave a slower 29.6MB/s read and 17.6MB/s write. While that doesn't make this an outstandingly fast NAS device, it does at least make it an honest one.