They offer warmth in the winter and a unique feel with a slight give. They are heavier but not by much. Care must be given to metal ferrules as they will loosen easily and once bent out of round will not go together well. Wood paddles are a must for homemade boats. Wood actually has long term durability and is easily maintained.
Shaft construction is similar in most composite paddles.
There is a major supplier in the U.S. for most paddle manufacturers. More custom shafts are appearing. Fiberglass is the most common material. Graphite is light, stiff and brittle. Wood is warm and nice to feel.