Hi all -- Thank you for the quick responses! Sounds like I didn't give enuf info. ;-) I've tried both Specialized and Trek aluminum and honestly, the carbon was a much softer, more comfortable ride -- I did feel the difference. I did not feel as "jarred" by small pavement defects, dips, etc on the carbon fiber as I did even on the Specialized Alum with carbon fiber forks. I'm curious on the question of longevity though -- that definitely interests me. One of the reasons I was leaning to cf was that everything I've read suggests that the aluminum frames tend to begin breaking down and losing comfort relatively quickly where the cf maintains its feel and spring much longer. If you've had different experiences, that I would definitely be interested in hearing!

Again, thanks very much.