The large size (15.6"), high resolution (it is actually UHD! Not like these other "4K monitors" which merely mean it can take a 4K input, but are only a 1080 screen in reality), low-ish weight & power demands (2Kg & ≤18W), and various features (SDI / quadview / PIP / etc) all make it quite appealing for the low price of around US$600!
http://www.seetec.cn/ShowInfo.aspx?...840x2160-4xHDMI-Quad-Split-Display-4K156-9HSD
http://www.seetec.cn/ShowInfo.aspx?...840x2160-4xHDMI-Quad-Split-Display-4K156-9HSD