Re:
I have a fairly wide variety of bikes, including steel, aluminium, carbon, titanium and carbon with alloy lugs. Ultimately carbon will always be faster, since it can better be tuned to give the right shapes and stiffness characteristics.
It's also vastly more than 600g lighter than steel - for example, my Condor Super Acciaio *frame* is 1800g (size 5
, while my entire Cervelo R5Ca frameset, including forks, headset and BB is 1000g. Built up with the standard Condor full carbon fork, Condor headset and standard BB30, the Super Acciaio is 2270g - or 1.27kg heavier than the Cervelo. In its lightest build, the Cervelo is 5.3kg with pedals. You can't do that with steel.
However, when weight isn't a deciding factor, steel gives a ride quality that most carbon frames aren't built to deliver - an absorbency that adds some fluidity to one's riding.
Steel is also better suited to the every day knocks of cycling, and (given this is Retrobike) just looks right. This is not true of the Condor, which has all sorts of weird hydroformed tube shapes and is lugless, but is very much true of my Zullo and of other classic lugged frames.
Classic looks aside, though, in my view titanium does everything steel does better than steel - lighter, better ride quality, looks good etc. So although I have steel bikes for looks, I ride carbon for speed and titanium for distance.
Let's not forget aluminium, either. Ride quality tends to be harsh, but it's light, stiff, cheap and tough. There's a reason why crit bikes tend to be alloy.
(oh - and carbon with alloy lugs? Haven't ridden a modern frame with this construction - IndieFab XS, for example - but my ALAN is great fun. About as stiff as cooked pasta, but remarkably comfortable and [I think] rather cool. Apparently you can see the rear triangle moving around like a thing possessed if you're behind me in a sprint.)