Last week I compared my new carbon Roubaix with my steel Marinoni. The Roubaix rides a lot smoother, less buzz by far. Hell it even has less buzz in the bars than my Rocky Mountain Sherpa 30 touring bike.
I have 25 or so steel bikes and one carbon. If I had to do a century tomorrow you can bet I will be taking that new Specialized Roubaix.
If I was going on a nice 30 mile Sunday run I would take the Marinoni but the steel bike has seen its last century for now.