Well, we clipped a tree at about 45mph during the 2003 OBC and hit one of my 5" KC HID floods straight on. It smashed the glass lens, but the light itself still worked, and in fact, is still working. I replaced the lens for $35 and it was good to go. The HID bulb, the metal housing, and mount were not damaged. So Lightforce isn't the only brand that can take a hit. If the 5" KC's came with Lexan lenses, there would have been no effect from the impact.
But then we don't really buy lights because of their ability to suffer frontal assault. We buy them for the light they produce.