The stiffness to weight ratio of a high modulus carbon fiber construction is typically 5 times higher than steel or aluminium.
Double curved shapes are easily produced in composite materials at almost no extra cost. For production of limited series the relatively low moulding costs are an additional benefit.
Steel structures typically require periodic maintenance such as conservation and paint systems to prevent corrosion. Composites are not susceptible to corrosion resulting in lower Life-cycle costs.
The fatigue resistance of composites is much better than that of metals. Of course fatigue failure also occurs in GRP and CFRP and has to be analysed in detail.
The specific weight of composites varies between 1.5 and 2.0 compared to 2.7 to 7.8 for aluminium and steel.
In general, fiber reinforced plastics outperform metals (e.g. steel and aluminium) in strength.