Shane Satterfield of GameTrailers has said that he is “definitely getting Assassin’s Creed 3″, and that, after seeing all three versions of the game on the various consoles:
…the Wii U version looks the best. It also has added functionality, so that would probably be the one game I’d buy with the Wii U, would be Assassin’s Creed 3.
Based on the videos, I haven’t noticed many (if any) graphical differences, but the improvements might be easier to spot in the real-world. At the very least, if the game has slight frame-rate drops in the other console versions, the Wii U should be able to handle those rough patches with ease.