I've had people make all kinds of ridiculous claims about CF components:

"Yea ... my bike used to ride really harsh when I had an aluminum seatpost. With the CF seatpost, it's really plush."

Plush? With something as stiff as CF and 90% loaded in compression? Compared to the compliance of the tires, the seat, and the seat suspension? Balderdash.

I had an straight gauge aluminum bike (with an aluminum fork too) and switched to a CF fork. My take on it? The difference is that when you go over a bump, the CF fork goes BONG where the Al fork would have gone BANG. That's about it. It's not like you'll get more vertical compliance out of the part ... you won't. But the vibrations don't "ring" as much.

That being said, the BANG versus BONG difference isn't terribly significant for short rides. But when you're talking about long rides on crappy roads, it does add up.

YMMV.