i think the titanium bike would be more durable. It is hard to say without evaluating the geometry and construction of a frame, i'd say that generally: titanium flexes a lot and a has a smooth rebound, where as carbon can be stiffer with a more snappy feel. I would say that in 2012, manufacturers have greater control tuning ride characteristics using carbon. both are great materials. i just purchased my first carbon frame a few weeks ago, and its taking me a while to trust its integrity. something makes me nervous about vehicles made of fabric and glue.