I don't have a full carbon bike, but I recently had the opportunity to see something on a two day, double century ride that made me never want to have one: Much of the ride was on the most brutal chip-seal and there was a woman there with a nearly new, full carbon Ruby that had a catastrophic failure of the chain stay which she attributed to the vigorous bumping and banging from the road. Dh's seat post bolt snapped around the same place on the course for (he speculates) the same reason, so it seems a pretty reasonable assumption that the road was reeeealy rough...