Depends on the design. In some, the core wood seems to make very little difference--performance comes from the design, with the glass doing most of the work--as in a wide, thin limb.
In a limb where the wood is making a difference, I prefer yew. Very similar characteristics to bamboo (light, flexible, fast recovery) without the nodes to deal with. Yew is a wood, bamboo is a grass--don't know that it makes much difference, but seems to me that the wood fibers will be more durable in the long run.
Chad