The differences are the amount or the concentration of oils that are in the scents. The higher the concentration of oils, the longer your scent will last, and the less you should need to apply. Are all of your products genuine?.
MILANO MAN L'EAU BLEUE EAU DE TOILETTE POUR HOMME AFTER SHAVE 50ml SPRAY
Guerlain Santal Royal Eau de Parfum 125ml
Vintage GUERLAIN HERITAGE 100ml Eau de Toilette spray
Issey Miyake L'eau Bleue D'issey Pour Homme Eau De Toilette Natural Spray, 75ml
YSL L'Homme Cologne Bleue 100ml Eau de Toilette EDT New Boxed No Cellophane Wrap
Issey Miyake Bleue d'Issey Eau de Toilette Spray 75ml Mens Fragrance Woody Scent