I'm a little late to the thread (but only a few months, not years!). I have both... I've been gearing up for the hotter than hell century and was trying to figure out which bike to ride, so I've been alternating rides on the two bikes weekly. It took me until two 75 mile rides 2 weekends in a row to decide - I'm taking the Ti bike. The 2 weigh very close to each other. The carbon bike feels sportier and accelerates a bit quicker, or at least it feels like it does. The Ti bike is smoother, but almost soft. Alternating my long rides on the weekends was a good test. I feel less tired/beat up on the Ti bike, and oddly enough my average speeds have been slightly higher on the Ti bike. I had a pro-fit done on them, and they are set up the same geometry wise, same seats, aerobars, etc.

And I may have missed it in another thread, but did you make your decision yet?