I will probably be attacked as a carbon-hater, but it has a tendency to fail catastrophically when you least expect it. Carbon tests as very strong in the lab, and I am sure people will protest that their carbon bike (fork, seatpost,etc.) is covered by warranty -all that means is that you might get a new one if it fails-it doesn't mean it won't fail.

I had a new carbon fibre ski pole shatter on me one day. I have never had a metal ski pole break.