Puma won't get 120Hz though, that's a TV feature, he'll only get 60Hz with a PC.
Most budget 4k TVs (in fact pretty much all right now until the nVidia big format gaming displays @120hz 65" come out), don't do 120hz in 4k from a PC, only in lower resolutions. They are all in 60hz at 4k. The only real option right now for higher than 60hz 4k is the Acer/Asus 144hz 4k 27" monitors. We have one Asus unit, at 27" I think the 4k is only really marginally better than 1440p, but these monitors have other benefits as well.
As said above, it's TV/GPU dependent and a bit random across the board so far as HDMI2.xx/etc standards and 4k working on a "gaming" TV. I have a couple TVs that are 4k and have specific PC gaming modes, 55/65" LG NanoCell units are inexpensive for the most part, and using a standard HDMI cable from the HDMI port on the 1080ti/TitanXP cards, I'm able to see games at 4k and 60hz on both of these TVs. IMO once the 65" nVidia gaming large screens are out, which will do 4k at 120hz, the LG NanoCell are one of the other options (there are a few other more or less acceptable PC gaming 4k tvs out there, lots of info on Google about this) but still limit you to 60hz in 4k.
When planning on using any 4k TV with your PC, Google that model and check the specific sites dedicated to 4k TV PC gaming, there are several out there. Input lag and other factors are important to know, some TVs will be better than others for PC gaming, but none will touch a gaming LCD in performance, not yet anyway (65" nVidia again).