Such a generalization is impossible to justify--as you know, F16s come from multiple manufacturers and are constructed with a variety of different materials, including marine ply, standard fiberglass, kevlar, and carbon fiber. I'm not sure where you're opinion about F16 durability comes from, but materials such as marine ply, kevlar, and carbon fiber are extremely strong and durable. Each manufacturer has their own process, and my experience in evaluating several different F16s have found them to be extremely well made and durable. Although I have only seen one I17, it seemed well made too.