I used the IGZO panel in the Asus panel briefly and it was stunning, put my U3011 to shame. There is a good reason it is more expensive, it is superior in every way and that is why the 4K ultra sharp will use it. Not very promising to see a VA panel is going in the cheaper 4K panel, VA=a lot more input lag than IPS/IGZO and less colour fidelity, but it has better black levels. The input lag is pretty bad on VA though.
As far as powering 4K, if your target is 60FPS steady, with today's hardware you are running modern games on medium to do so with dual Titans, unless you are willing to deal with sub 30fps minimums to raise settings.
I expect dual 20nm flagships to allow maybe high settings and 50-60fps minimums in a game like Battlefield 4 at 4K. GPU hardware is nowhere near ready for 4K at decent settings and framerates, unless your plan is quad fire/quad sli of the best cards on the market.