Carbon bikes are SCARY! Steel bikes have been around for a hundred years. Carbon bikes from the 90's (many just carbon wrapped tubes) are scary! It's unpredictable. You scratch it, it becomes an issue. You nick it, it's an issue.
I work at a Trek dealer (HUGE carbon pusher). During the last seminar I asked about the longevity of their carbon bikes. They replied, "That's why we have the best warranty in the industry". I said, "How do you warranty teeth, broken bones and Doctor bills"?
I had to have a meeting after the seminar because I was "out of line" for questioning them. :roll:
I took a composites class in college. I will say, they have a pretty good handle on the manufacturing of carbon parts, but steel and aluminum have proven themselves. I'll wait another 10 years to see how carbon does.