The people at GizmoSlip have made an entire Youtube channel out of dropping expensive electronics to see if they'll keep working after succumbing to Newton's fury. The Wii U GamePad is no exception and they put the poor thing to the test, dropping it repeatedly from a height of four feet onto bare pavement, from a top, bottom and side angle.
The intrepid GamePad survives and continues functioning normally, albeit with a few scratches. I know it's just technology, it's one of the controllers from the ripoff basic white bundle, and it's not my Wii U, but I still can't help but cringe when they drop the innocent little GamePad. It looks like the Wii U continues Nintendo's legendary hardware durability--as I recall, you could drag a GameCube by its cute little handle behind a pickup truck and the thing would still function. I'm not sure about the Wii's resilience; I never felt like taking a sledgehammer to it like I was tempted to with my 360.
At least parents can know that the pricey new console they got for their kids will survive some rough play...for a while anyway.
Also be forewarned, there's a huge annoying plug in the middle of the video for the channel's sponsor so you might want to skip over that.