Some of the benchmarks are starting to come out of the vanilla Apple A9 processor and it appears to be quite beastly. The A9X in the iPad Pro then it would seem probably is a good deal better than the Wii U/PS3/360. Looks like we're definitively crossing the threshold of that gen graphics and now the march begins to match PS4/XB1 levels.
Gotta wonder if that A9X chip could be in the AppleTV next year but it's amazing how much Apple and PowerVR are improving every year in the processing power department.
I would not honestly mind if the NX is basically just a chip like this, this is roughly 15x more powerful than a Vita. Not only that but the A9X has a monstrous amount of memory bandwidth for a portable device at 50GB/sec.
I have to wonder if at 960x540 resolution if it could maybe even handle PS4 engine ports. Of course not many devs will try.