By far and away the worst bike I have owned was an aluminum frame / carbon fork / carbon stays bike . It was very stiff and transmitted every bit of road vibration to you even with 25 mm tires which were the largest ones that could be fitted to it. Granted I did not find it an especially comfortable bike because I am larger rider , but honestly I do not think a frame that has a supple , compliant ride is a bad thing. The vintage steel road bikes I own are fast enough to satisfy any need for speed I have , and they satisfy it comfortably.

As an aside no argument can be made from my perspective for the weight savings carbon offers since I know that a steel bike can be made just as light as a carbon bike ... The Rodriguez Outlaw is a good example.