seat post

I'm upgrading the seat post for my Cannondale optimo 3. Came with their "C2" which is aluminum post carbon wrapped with a setback. I had replaced it with an Easton EC 90 very elegant but alas no setback. To fit it I had to move the saddle back so far on the rails that it was at the curve. Is there any advantage to a carbon post for this? I wonder if it will take up some of the road buzz as I use this bike for winter training and a race now and again. Will the carbon post hold up to the cross racing? Clearly there is strong support for the Thompsen, which I would go with for aluminum. I do want the two bolt method of adjusting the saddle angle (one of my pet peaves with the canondale).