I wrote them again. Here is the bullcrap answer they gave. I asked specifically the construction changes from the VariX III and the VX III and the difference from VXII and III and VariXII and III. They will not be more specific than this.

Leupold Customer Service
Product Specialist Group
Phone (503) 526-1400
Reference Call #

Caller: - Mark
Summary: scope options

Mark,
We recommend the VX III for the optimum performance in low light
hunting conditions. The optical differences between the two scopes in
question relate mostly to light transmission and low light performance.
There will be no difference in the ability to handle heavy recoil.

Garth
Support CallID: %#%01cf36ea-f571-4323-ac6e-26a99e827b37%#%