Hmm, mostly seems to be differences in the lighting, but neither looks better than the other. The only point one looked better is during the conversation with the captain, the main character's face looked more detailed in the 360 version.

When the ship comes in on the scene.  That part.  360 its a black mess.  WiiU you can see the detail of the ship better.

Just so one thinks this is a bad sign, remember that the Xbox 360 launch games looked almost exactly like the Xbox/PlayStation 2 versions of the games too since developers don't put as much effort into their launch port games.

I simply see higher textures on the 360, but better lighting in general on the Wii U. Over time, the Wii U will have the best of both.

Wii U seems brighter but lower contrast. Only notable difference is the lighting on the face of the character during the conversation near the end.

I'd love to see how it stacks up to the PC version (with highest graphics settings, of course.) If it weren't $50 on Steam and I hadn't just spent $60 on it for Wii , I'd totally be all over this. Alas, however, I've spent too much money already this past week for me to be buying duplicate games. :/

PC would win hands down--the only version of AC3 that has tessellation enabled.  The WII U has an tessellation unit (according to the specs) but I don't see any game using it. 

Tessellations makes everything more "3d"ish so you'll notice stuff like cloth and objects stick out more.