According to Digital foundry, whilst the Wii U version of Black ops 2 does look better in some cases, it does suffer from a severe inconsistent frame rate at other times. One moment a good solid 60FPS, at other times down to 30FPS.
The Wii U is a new system and according to some, devs only had the final specs for 7 months or so before release. It take much more time then this make a consistent port in most cases, especially for hardware and system tools that developers aren't used to. Hopefully by next year, when devs have had more time with the console and games are being developed with it more in mind, some of these issues will fade away.
It's good to hear sales figures are good though. I can't wait for mine to arrive on Friday!
Something's coming up the plumbing, poor Luigi's in a bind. Giant turtles are out to get him, Creepy Crabs are right behind. Spiders, flies. Jeepers! Yikes!, They're coming out the pipes. "MARIO! WHERE ARE YOU!!!"