The latest batch of cheap 4K tv's come with HDMI 2 allowing 60hz. Since I needed a new monitor for work, and just to test, I bought a 43" 4k Vizio E43U-D2 for $450, expecting it would be a failed experiment and then I would know.
Oh my god I love this TV as a monitor. Since it doesn't have a tuner, it essentially is a glorified display with home theater hookups. I work in a lot of applications at once and connected to multiple RDC sessions all over the world. 4K is plenty of resolution to sit close and focus on just the area of the monitor I'm working on at a time. All the extra HDMI ports allow me to hook up a game machine at the same time, and the optical out lets me connect to an older, but still very nice receiver.
I've been working on 60hz for years with traditional PC monitors and its fine. Mouse tracking is smooth. Color seems about right.... I am not color correcting to press on this monitor. For gaming, I push my seat back a bit and enjoy super high rez. I have a gtx970 and honestly it does just fine in 4k for an awful lot of older games... and I can easily switch to a lower resolution if I need to.
Economy of scale makes this way cheaper than something equitable made for computers. I'm sold on using a TV as a monitor now that HDMI 2 ports are available on the cheapest models.