Great treatment of iris root. It's there at all times; in the green soapy topnotes; in the rootlike yet powery heart; in the dry double root base of iris and vetiver.
We tend to compare iris fragrances. The scent of iris root and the aromachemicals used to recreate it comprise such a particular yet complex set of notes that comparison is almost inevitable. Dior Homme, Chanel 19, Iris Silver Mist, Ferre by Gianfranco Ferre. Yup. The most directly comparaable perfume, though is the wonderful and underestimated Bas de Soie from Serge Lutens. Iris Bleu Gris doesn't have Bas de Soie's metal cum hyacynth notes, but otherwise the heart and base, and the trajectories they follow are very close.
We speak as if Dior Homme created the first masculine iris. Jean Laporte thought to release an iris-centered fragrance in the early 1980s and it's still with us 30 years later.