I think hardware wise we'll be looking at
720 > PS4 >>>> Wii U
2TFLOP+ performance for both the 720/PS4, but MS will pony up a few extra bucks to get more RAM and few other bells and whistles into their system because they can afford to eat a loss to win the living room.
I also don't think the Wii U will be that close to the 720/PS4. You will notice 2TFLOP vs. ~300-350 GFLOP in performance difference. Especially as this next-gen goes on and more and more games start to take advantage of the 720/PS4. It's not going to be some small difference, it will grow to a large chasm.