A carbon post alone is not a spectacular addition to a bike, or a big weight loss, etc. Its the sum of the parts that add up.

My bike is not light because it has a carbon post, its light because it has a carbon post and SLR saddle, Record Ti, carbon cranks, etc, etc. My bike doesn't have good vibration absorption from the carbon post, but it does have it from the post, the saddle, carbon and ti frame, tire choice, etc., etc.

The post is one part in achieving the whole.