Well, what refresh rate stuff gets into the TV, what it is actually displayed at, and what it looks like are different things.
That is why a particular TV has to be seen to know whether it actually works as a monitor. At this stage, all anecdotal observations/reviews are that the Seikis appear to be a reasonable 4K monitors, as long as the vertical lock is off. The Seiki site even proffers their use as 4K monitors. They are not gloss screens either. However, the same reviewers cite that as Full HD TVs, there are much better TVs at lower prices.
Until DisplayPort connections are included, they (and any other HDMI 1.4 only TVs) are just not going to cut it for gamers, or video professionals. Mind you, Red (professional video camera makers) bought heaps of them.
If one wants to run 4K video at high refresh rates, multiple top-end video cards are required, which is why I suggested feeding video in at lower resolution into another monitor or an actual TV(with overscan off), or timecode sync to a separate video machine.