Outside of the Wii U GamePad, the other controller that Nintendo had on display in its booth was the Wii U Pro Controller. A more traditional controller, the Wii U Pro is another option of playing games on the Wii U. Between this, the GamePad, the Wiimotes, and the Wii Balance Board, the Wii U can now officially be controlled more than 17,000 ways.
Since the Wii U Pro is actually very similar in look and button placement to the GamePad (sans giant touch screen), I will keep this short and get to what you most likely want to know: Is it comfortable?
In a word, yes. Absolutely. It is a little light for my taste (its weight falls somewhere in between the original PS3 controller and the updated DualShock 3), but it sits very comfortable in the hands. In fact, it feels (and even looks) very similar to the stellar Xbox 360 controller.
The analog sticks feel great (yay!), and even though the face buttons are under the right analog stick, it is not as weird in practice as it sounds. Shoulder buttons and triggers (like with the GamePad) also feel good.
While not many games on display used the Wii U Pro Controller, I am very happy Nintendo introduced it to the extended Wii U controller family. It is like the cool uncle that may not live with you, but is always there when you need him.