I am trying to decide on a new bike, two are aluminum (Cannondale Synapse 5 or Specialized Allez Elite) & two are carbon fiber (Fuji CCR3 or Scattante Pro). There was a thread a few days ago that should catastrophic frame failures and I was wondering if this common? Is there a limited life cycle for the frame? Will an aluminum frame be a better choice for someone 200 lbs.