I have the 55" model which I got from Sears(they are the only place to carry the 55"). With MEMC on there is a noticeable lag when using the mouse therefore not good for gaming. HOWEVER, with it turned off I did not see any lag whatsoever. I have played Crysis 1,2,&3 and the best are 2 & 3 when it comes to the beauty of the rendered graphics at 4K. I play mostly in stealth mode in Crysis so the run & gunners might have a problem with 30FPS. Crysis 3 also allowed 3D mode. I need to get some 3D glasses and see if it will actually work. Crysis 2 had the 3D mode "grayed out" but I do not remember if I was in 4K or not, I need to try it at 1080P.I downloaded some 4K video clips from YouTube and they looked fantastic.I really do not think this has the capability of a firmware upgrade. However, for a general TV this works well if paired with a good upscaling Blu-Ray player or current console such as the PS4 or XBOX1. For anyone that wants an entry level 4K this is a VERY good deal. As a computer monitor it will work well with out the hassle of multiple computer to monitors connections for a surround setup. This TV is for family viewing so HDMI 2.0 is really not that important.For someone that is codeing or in the financial industry WOW!!! I am a trader and I went from 6 MVA [email protected] 1920*1200 to 3 IPS monitors @ 2560*1440. Since CES 2014 there will be a bunch of 4K monitors at every size from 27" and up available soon. The pixel density of these smaller monitors should make for a beautiful picture. When the dust settles a bit I will make a choice of what new 4K with DisplayPort and HDMI2.0 to get for myself.Currently these are $799 at Sears, Amazon has the 50" for $999. If you know how and what you are going to use it for they are a VERY GOOD DEAL. For PC gamers, at this point, I would wait for the new models to become available. I think that 60FPS on a large(50"-55") 4K is the same as 120FPS say on a (24"-27") 2560*1440 because your target size is larger and crisper on the 4K .