Carbon fiber hoods from what i've seen are great overall if your looking for looks and light weight hoods. The only problem i have with them is the fact that most companies give you ones that are offset or not properly aligned with the body. Other than that they do have their good qualities.....their light weight.
Not sure about the price being worth it but the looks and weight saving is definitely worth it. They generally won't fit as perfect as a factory hood but the top end companies like Fiber Images and Spoon do get pretty close. Check some out at car shows and see what fits best and go with that.
CF hoods are pretty strong, and I dont think they dent easily as opposed to a regular hood, of course also mentioned above the weight saving. Make sure if you get one to get hood locks, I have heard stories of cf hoods flying open on the highway etc, not something you want to happen.