I remember the early Specialized Allez carbon frames which outright sucked -- it was like riding one of the skinny-tubed Vitus aluminum frames.
I have a 60 cm hanging in my basement right now. I always hated it. Worst climbing bike ever. It sucked the power from the pedals right into the frame, NOT the wheels.
Carbon bikes today are completely different. Most serious frame builders have got a handle on carbon.