With its cute and functional design, fast (although dated) hardware platform, small dimensions, USB 3.0, two Ethernet ports, and tool-less hot-swap HDD bays, the Sentinel DX4000 is a step forward for Western Digital on the NAS market.
As opposed to the hardware, Windows Storage Server 2008 R2 Essentials has left us rather perplexed. The fact that it’s Windows is good in itself as this may be necessary for some usage scenarios. It’s got a handy backup system for Windows clients and an interesting remote access feature. However, this version of Windows is rather difficult for non-specialists to manage. The default firmware doesn’t provide many popular capabilities such as FTP server, UPS support, multiple disk volumes, iSCSI, extended backup copy options, notifications, and mobile apps. Of course, many of these features can be implemented in Windows, but you need desktop access and full-featured OS administration. It’s unclear how the standard WSS environment will react to new applications, though.
So, if Windows is not a requirement, Linux-based NASes seem more appropriate for home and SOHO users right now. They offer broader functionality out of box. They are easier to set up and manage.
As for the price factor, the Sentinel DX4000 is shipped with enterprise-class HDDs which are quite expensive. That’s why it is not affordable, even though not very expensive, either.