As other posters have indicated, any of the current frame materials, if properly constructed, provide a comfortable and efficient ride. I've built and ridden a number of Al frames, including a Masi Gran Criterium (CF seat and chain stays), Specialized E5 and Principia Evolution SX. Only the Principia provided me with a ride that was comfortable enough for 5+ hour rides. I ride the Principia regularly. Although I really enjoy the ride quality of my Tommaso Ti frame, it is a bit "noodly" as compared to my other CF, Al, steel and Mg frames. But, my Tommaso is definitely not a high end Ti frame. As long as you purchase a high quality frame, in a size that fits well, with good components and appropriate wheel/tire combination for your style of riding, you will find it meets the requirements of all but the highest level racers. In my case, it has never been the machine that determined race results.