I just picked it up a few weeks ago (Zombie U bundle along with Lego City, Super Mario Bros U, Scribblenauts Unlimited, and CoD BO2).
As I mentioned in another thread, it is best to think of the Wii U (at least with its current library of games) as a companion console. I almost never play the system by itself (unless I want to play a game that can not be played only on the pad). I usually play games like CoD BO2 and Super Mario Bros. U on the game pad in order to add a little variety when I am gaming for a longer period of time on the Xbox (4-6 straight hours of even a great game can get a little repetitive). It is also good for downtime in another game I am playing and for when I am waiting for a friend to come online. As an added bonus, the game pad has effectively replaced my TV remote. Also, you can watch videos on it as well so I often find myself in the situation where I am watching a Amazon Instant / Netflix video on my Wii U gamepad while playing an Xbox game, and surfing the net on my laptop (love to multitask).
It is really a great little system, but I would hate to just have a Wii U without an Xbox/Playstation/PC to pair it up with.
