So, I actually really like my carbon bars. They are Zipp bars, so the carbon is (or so they say) better quality... But I think they were worth every penny. Riding in west Texas was impossible without them. I noticed a huge difference right away in how long it took before my hands went numb and how much noise I could hear associated with the hoods/computer/headlight rattling on the front of the bike. I think the road is very much smoother with them.

Out here in the big city where they have never heard of chip seal, it's like riding on glass. So smooth.

So that's my vote for carbon.

(If it makes any difference to you, I ride Vredestein tires at 130 psi that are 23s)