The modern ARM platform has proved to be quite appropriate for midrange NASes. It is as good as the x86 platform unless you've got some special software to use or plan to load your NAS very hard.
Talking about the particular model, the QNAP TS-419P II is a typical NAS for demanding home and business users. It offers four disk bays for up to 12 terabytes of storage. You can also connect external disks using its eSATA and USB ports. Its two Gigabit Ethernet ports can be used to connect to different networks or to ensure higher bandwidth or reliability. Its data-transfer rate is high for its class.
QNAP’s firmware offers a lot of extra features that transform this NAS into a powerful server. The TS-419P II can work as a web or video surveillance server, download files from the Web, stream multimedia files to compatible devices, etc. The recently added features include Syslog and RADIUS servers and an antivirus plugin. The QPKG package management system helps you easily install more packages (email server, content management, blogging and many other systems).
Home users will appreciate the nice-looking exterior and high quality of manufacture of this product. Its cooling system is efficient and quiet (but four HDDs may prove to be too loud for a bedroom). The only thing I don’t like in the design of this NAS is that it comes with an external power adapter although its case might have accommodated an internal one, like in QNAP’s top-end NASes. The integrated display is not very functional as it is accompanied with only two control buttons.
The TS-419P II costs somewhat less than NASes based on the x86 platform, which looks like perfect positioning to me.