The one we've done runs on Linux. It's the same as our Linux version. Audio, video, and images. I think its value on the QNAP may be as a DLNA Server, but I'm not sure.
Some (all?) of the newer QNAP models have an HDMI port (or two) allowing the NAS to be connected to a device (e.g AVR) for, among other things, multimedia playback. Currently, I believe the only way to use the NAS as a media player is to install the HD Station software and the apps contained within. But there may be an opportunity here.
For those of us with multiple media players (running MC), being able to use a NAS as a Library Server would be a great benefit. I currently have multiple libraries because I am not going to run the "main" media server 24/7 just to make the library available to the other media players the odd time they need it.
DLNA Server - sure.
The, now in beta, QTS 4.2 will include:
HD Station apps:Plex™ Home Theater, DeaDBeef, Clementine™
Browser: Chrome™, Firefox®
Multimedia streaming: YouTube™, Spotify®, Tunein™ Radio, Popcorn Time™
Communications: Skype®
Document editing tool: LibreOffice®
Small games: SuperTux™, OpenTTD, Wesnoth™
QNAP tools: QTS, QVM, File Station, Photo Station, Music Station, Video Station, and Surveillance Station
Included but not listed is XBMC/KODI.
QNAP is putting a lot of effort and resources into making their NAS devices useable as multimedia center / HTPC devices.
Is what you currently have available for download and how complicated is the installation?
Cheers,
Gary