Jonathan,

They both ride very smoothly, and you can't really go wrong with either one.
It's been stated numerous times, but it's very true: fit is the utmost important aspect of bike selection.
I just got my first full carbon bike a few days ago after riding a Ti frame for 2 years.
I like both frames a lot, and they both have their advantages.
The carbon bike has a little snappier acceleration due to some weight savings and slightly increased stiffness. It’s impossible to give you the right advice without knowing what your goals are in the next few years. You should talk to a reputable local shop and figure out what would be the best fit for you. The worst thing you can do is focusing on the frame material alone.

Cheers