Absolutely nothing new to read here folks - Mitsubishi already had a 3840x2160 quad HD monitor available a year ago (56P-QF60LCU). The price at that time was around $50,000 if I remember right.
The problem with the technology, other than requiring a brute-force PC with 4 HD video outputs to harness the resolution, is that you can only display static images. 1080p video will not look any better at all. On the other hand, if you're into serious CG, CAD or digital artwork, this monitor will make your jaw drop to the floor and your eyes bug out.
Not to disappoint movie fans though, film does have a native resolution of 4096x4096, which means QHD video IS possible.
So, if you think you are rich and can blow 50K on this monitor, how about you invest another few million with your other rich friends into the technology to convert 35mm film into QHD video, and while you're at it, invest another few hundred million to develop the storage/playback technology.
It will probably be at least another 15-25 years before we see QHD video broadcasts, due to the sheer bandwidth requirements (250MB/s uncompressed), so you can forget about that QHD TV as well.