Although fibre lasers have made tremendous progress over recent years, claims that they are about to replace more conventional types in metal cutting, due to their ability to achieve similar or superior performance at lower cost, are premature. True, fibre lasers offer key benefits: they are compact, flexible, reliable, and achieve an excellent beam quality due to a design that essentially eliminates thermal effects. However, they are limited in terms of peak power; they are also expensive and complex, which is a problem if things go wrong.