The differences between the 2 are that the VXIII has a one piece tube and is multicoated on all lense surfaces. The other is a 2 piece tube and has Multicoat on the exterior lense surfaces only the interior coating is something they used on the old VARI x II. The VXIII will be brighter than the VXII and should be a lighter scope when comparing other Leupold scopes of similiar power and objective size and will probably have better eye relief. You can find these answers in the FAQ in Leupolds home page. They both have click adjustments. I bought a 3x9x40 VXII this year and was not impressed by it at all. If I continue to buy Leupolds it will be the VX III series.