I have steel, aluminum, titanium and carbon bikes. Can't say that the difference is significant.

The carbon Look rides really smoothly. The carbon C40 rides rather rough though it has fine handling on fast downhill rough stuff. The steel Basso is a really great riding bike as is the Colnago Super and the Eddy Merckx Corsa 0.1. The titanium Eddy Merckx Ex is the best balance of everything but the differences hardly matter. The aluminum Fuji Newest rides almost perfectly.

Bikes that stunk - one of the original Colnago Masters. So stiff that your eyelids would roll on a rough road. My Colnago Super with the original steel fork. After changing to a carbon fork the bike was transformed from a mediocre bike to a top handler.