I listened to a podcast featuring Gary Loomis and he said that although graphite has a higher modulous than fiberglass, it has much less hoop strength. Modulous is the resistance to bending whereas hoop strength is the resistance to crushing. the higher the modulous the less hoop strength. So that said fiberglass rods will almost always be more durable and the higher the modulous of graphite used in building a rod, the higher chance of rod breakage. I imagine resins have improved graphite and so has rod construction. That being said I can't imagine a graphite rod being as tough as a fiberglass.

Wayneb