Don't get me wrong, I think carbon is pretty sexy. I've got carbon bars on my rig and they do exactly what they're intended to do...look great. I have an old racing friend from way back that has been a product manager for ITM for several years. He told me they did volumes of testing and found their aluminum bars muted vibrations as efficiently, if not better than their carbon bars which were stiffer and used more material mass which they said conducted vibrations just fine. This also explains why so many Pro Tour riders were opting to use aluminum bars over blingier carbon bars. That trend is changing because as was said recently by the head Fred at Deda - fewer high caliber aluminum bars are available.
You also have to take into consideration the frequency of vibrations that in theory could become troublesome for a rider. Those vibrations that carbon can effectively mute (again in theory) are extremely high frequency vibrations. Such vibrations on mountain bikes simply don't travel through fat tires, spokes, forks, rubber grips, padded gloves, etc.
Carbon has an interesting affect on people's perceptions and expectations. If carbon is capable of soaking up vibrations, how would you predict the ride of a Cervelo P4 TT bike with 90mm deep carbon wheel up front, full disc out back, carbon saddle sans padding, carbon bars sans tape and only 2mm of neoprene on the elbow pads. Oh, and 20mm tires up front. Ya....that's a lot of carbon and you better believe that bike would ride like a jackhammer.
It took me around New Zealand with racks held on with pipe hangers. It has had a tough life, and 20 years on, I still ride it like it was new. I can't say that about the steel or aluminum bikes I've owned. Something to consider when choosing a bike. 
