I'm impressed by the graphics! But I am mostly impressed by the fact that there is a real platform-ish adventure "cartoon-ish" game in the works! Its called Knack! I really liked that and the Knack character looks badass XD
But I also think, even if the PS4 has much better graphics and stuff, the Wii U will probably still be able to take some of those games that is coming out. Remember back when PS3 was announced? The games looked very last-genish, like just a step up from the Wii graphics. During the evolution of PS3, the graphics was becoming MUCH better and I think this will also happen with Wii U. What we've seen, as games yet, looks like a good first step. Remember that Japanese garden gameplay video they showed at E3 2011? And the Zelda Wii U "game" they also showed? Those graphics were almost as good as these for PS4 and I bet that the Wii U is also able to produce almost the same as PS4.
And if I am wrong? Well whatever XD
I might buy a PS4, but I aren't sure. I wanna see which games comes for it first, but if I'll get it, I will buy Knack for it!
But still, remember, it isn't about graphics. Its about the gameplay. If the game aren't fun, why bother play it, just for the graphics? When I play games on my Xbox 360/Wii U, I don't notice the graphic anyway, because I am focusing the on the gameplay.
Gameplay <- Storytelling (if any) <- Graphics, IMO.