I love a good steel bike as much as the next tedious man in his thirties, but I don’t think steel deserves the almost mythical status it now enjoys.
If you want a bike to be as light and stiff as possible and you prize these characteristics above all others, make it out of carbon. The very lightest steel frames weigh more than very average carbon ones, and steel bikes that manage to be truly light only do so by virtue of using expensive high-end