I recently posted an article on the Western Digital My Book Live Duo Network Attached Storage Device. It is actually a great multipurpose, network data storage device and media streamer that lets you access your data from anywhere you can connect to the internet using your computer or smartphone.
Western Digital just released another version of this network storage device, this time with Thunderbolt connectivtity. If you are not familiar with Thunderbolt (also known as Light Peak), it is an interface that Intel has recently developed as an alternative to USB that is used to connect external devices to computers. Theoretical transfer rates for Thunderbolt connected devices top out at 10 Gb/sec, compared to 5 Gb/sec and 480 Mb/sec for USB 3.0 and 2.0 respectively. Given limitations on read/write speeds on hard drives, actual rates will be much lower, Western Digital lists an expected transfer rate of about 250 Mb/sec. The two Thunderbolt connections on the back of each NAS, allow the user to daisy chain up to six of these device which would increase your storage up to 36 TB. Apple is about the only computer manufacturer that has jumped on the Thunderbolt wagon so far, so unless you have a 2011 and newer model of MacBook Pro, iMac, MacBook Air or iMac you not likely be able to connect to this device. Also, since this would be connected to a single computer, either a desktop or a laptop, it would not likely have the networking features that the regular model has, that connects to your router.
The Thunderbolt version of the My Book Live Duo comes in 4 and 6 TB models with price tags of $599.99 and $699.99 respectively, this is $200 more expensive than the models without the Thunderbolt connection.