I have had it for three months now, with four 8TB disks. It serves as storage space for photos & videos as well as for my extensive collection of movies and series. I can say (as an IT professional) that the combination of hardware & software is amazing. Anything you need from software is included in its operating system (DSM 7.x). It automatically backs up whatever you tell it to in well-known clouds, has snapshots to restore your files in case of a ransomware attack, gives you access from anywhere, and a thousand other things...
The icing on the cake is that you can turn it into a Plex server and have an amazing environment for movies/series on your smart TV/Android TV/Apple TV at home or even on your mobile/tablet from anywhere! Thanks to its Intel QuickSync, it plays everything, even 4K with 100Mbps+ (for those who understand). Tremendous purchase!
The only thing I would recommend is to buy it from a store that buys from the Greek importer. Trust me!