There's no doubting the enterprise credentials of the WD Sentinel DX4200, which with its solid yet compact chassis, enterprise-class disks and extensive redundancy features really does stand out from the general NAS crowd. It is, however, designed to fit a specific niche, aimed primarily at companies with existing Windows servers wanting to add network storage and nothing more. If that's you then the DX4200 fits the bill nicely. If not, it is still worth considering but faces stiff competition in a very crowded market.
The separate boot disk is a real plus point, making it possible to use all of the capacity of the removable disks for data. It also speeds up installation and, if you opt for a second boot disk, adds valuable extra redundancy.
We also liked the flexibility afforded by the Windows Storage Spaces technology which lets you get on with the job of delivering reliable shared storage without having to understand the complexities of hardware RAID.
The WD StorCentral dashboard is a nice feature but it doesn't really do much, handing you back to Windows Server tools when it comes to all the important bits, most notably, storage setup and management. Unfortunately getting to grips with the tools and technologies involved can take a lot of time and effort and is a lot more complicated compared to the best of the Linux-based NAS alternatives.
We've also become accustomed to being able to download and host a lot of free apps on Linux-based NAS appliances and these simply aren't included with the DX4200. You do get 25 licenses for WD SmartWare Pro backup, to protect user PCs plus the Windows IIS web server. However, if you want to add anything else (which is possible) you have to source it yourself.
A well built storage appliance with lots of enterprise-class features, the WD Sentinel DX4200 is most likely to appeal to existing Windows Server customers wanting to add distributed network storage to their setups. The choice of Windows Storage Server rather than Linux makes this easy to achieve but, by the same token, puts the WD appliance at a disadvantage when it comes to customers looking for a more self-contained, easy to manage, storage solution.
Worth looking at but take time to understand the positioning before making a buying decision.