FWIW, I threw one of the controllers into a wall hard enough to leave a dent (in the wall that is) when one of the straps broke during Holoball and was certain that it was broken. But it still tracked and worked perfectly and continues to work to this day - I've used the same pair of controllers since the Vive launch.
It seems like there are touchpad issues with some controllers, but I really can't fault their overall construction quality after that experience.
I feel like I'm been pretty damn unlucky. My two current ones are having tracking issues now, but I'm pretty sure that's because there's a lot of reflective material near the tracked area. Hoping I don't have to buy another two lol.