We have several NX Witness servers running on good quality Asus generic PC hardware, on Linux Ubuntu 14.04. Running on Linux makes it much easier to remotely manage & monitor than Windows.
Very stable, very reliable, very good user interface. Also very fast & user responsive, low resource usage.
The new NX Mobile app is better, even quicker at showing cameras, good streaming, great wow factor with potential customers.
Always pleasantly surprised when highlighting an object with the 'smart search' the movement timeline instantly showing the movement of that item in red checkmarks in whichever zoom timescale your on, even months.
The user interface is a lot of auto-magic, it's always trying to predict what you want and auto-prepare the answer, not waiting for 'ok' or 'save'.
We purchase it in New Zealand from NFS National Fire & Security, $NZ200 per camera.