Maybe easier to by an ARM based nas.
Just buying something overpriced and of limited functionality is always "easier".
But building a NAS with something flexible like the Cubieboard is much more rewarding, you'll be able to install various helper software, XBMC, use a monitor with it to make maintainance easy and faster than through some browser interface. And of course you can use this NAS as a TV box too.
At the same time, it will be a lot less of a ripoff than a Synology box, where they charge you another $75 for every 256MB of RAM they add. I understand this won't replace their 4xx or 2xx series with a single SATA port, but it will wipe the floor with their 1xx series while consuming less power. 4TB drives mean thats enough for a LOT of people...