Perhaps we should reframe the question. What would be the best frame material for a sub 700 gram frame? What. Would be the most comfortable endurance bike sub 1,000 grams. What is the most durable 2,000 gram frame set. In reality carbon would be superior in each category. Tell me any material other than carbon which could hit sub 700 grams remain reliable at mass market pricing. How about comfort, no way any titanium frame is as comfortable as a Roubaix or Domane. Carbons amazing weight to strength ratio as well as total flexibility regarding layup means it is unbeatable in any cycling related arena.