40-some years ago, when I was riding 400 miles a week in preparation for weekend races, I rode a Fausto Coppi 60 cm road frame made of light Columbus tubing. My friends said the frame was ‘whippy’, but it also was very comfortable to ride for hours at a time — that is, not much vibration was transmitted thru the frame. Then, to have an opposite kind of experience, I bought a 60 cm frame made of heavy Columbus road tubing. I discovered that it ‘beat me unto death’ and was not suitable for 50-mile training rides even on the relatively smooth roads in eastern Florida. So, I used this new, stiff, frame for criterium and short time trials only. It gave me a 20-second advantage in a 10-mile time trial over the Coppi frame. I think it sprinted faster, too. And so, to wrap up this long narrative, I do think that stiffness matters as does shock absorption when it comes to comfort over the long haul.