I know I'm always the optimist when it comes to Nintendo, but maxwell architecture is far superior to r700 architecture inside Wii U, a direct raw flops to flops comparison without architecture adjustments puts x1 at 3 times as powerful as Wii U. Maxwell handles its performance much better than even GCN and sees those peak performances much more often, and contributes to the ~33% better performance than gcn found in XB1. 720p requires only about 600gflops to match xb1 at 1080p in the same architecture, considering 16fp is perfect for most post processing and maxwell is a better architecture hitting its theoretical performance more often than gcn, even the 512gflops number could be enough to match xb1 at 720p and then we get into dynamic resolutions and checkerboard rendering, it is too early to say what this hardware can do but it can definitely get current gen ports targeting 720p on this device.
Having said the above, don't expect 1:1 comparisons with xb1, it will be noticeably slower than xb1 but thanks to the cpu being faster and the ram being comparable, it should be fine. It really only has to find its place in the market, pokemon will help with the raw numbers but gamers are going to have to buy ports and Nintendo is going to have to push for the mature market.