Summary: Superb device, note - it is often cheaper to buy external housed drives for this and take them apart - cheaper than a bare drive !! - and you get a couple of spare usb 3 3.5 cases if you do that. QNAP is fantastic, the firmware and apps are first class. Just the job.
Summary: I've given this 2 stars because it is possible that it might be OK for an expert user. From my point of view however it scores zero stars. It was fiddly but not difficult to install the new WD Red hard drives that I had also bought from Amazon, and the Cloud-based initialisation works beautifully. However the product cannot actually be used until a host of other settings have been made, because nothing is enabled by default.