What are your roads like? If they are mostly smooth, well-maintained asphalt I'd go with the CAAD...but if they're rougher (like chip-seal), then the carbon is well worth the money. A friend of mine had a CAAD9 and is now on a custom titanium Seven CX bike...she merely swaps out different wheels/tires for road or off-road riding. The titanium really dampens the road buzz. Pretty much anything is better than aluminum for vibration dampening.