XBitLabs recently released a fairly comprehensive review of the Western Digital Sentinel DX4000 NAS, a 4-bay NAS made by Western Digital, primarily known as a hard drive manufacturer.
XBitLabs put the Sentinel through its paces, including a speed test as part of their coverage:
The peak read and write speed are 100 and 80 MB/s. The external disk is comparable in performance to the dual-disk RAID1. Compared to other NASes with similar hardware, the Sentinel DX400 is somewhat slower than average.
Overall, XBitLabs appear to think that the Sentinel is a decent but not necessarily incredible NAS device. The main thing that seemed to really throw them off was the use of Windows Storage Server 2008 R2 Essentials as the software basis for the NAS:
A few examples of products:
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.