There are subtle difference between the two.
The VX-3 has Leupold's new XT Twighlightwith Diamondcoat 2 and blackened lenses.
Offers 98% light transmission.
Has finger adjustable 1/4 MOA adjustments.
Available with 1" and 30mm tubes.
1" scopes have 58 MOA
30mm scopes have 116 MOA
Utilizes fast focus eye piece.
Purged with Argon/Krypton gases.
And can have the availability of an illuminated reticle.
The VX-2 uses the same coating on the lenses as the VX-3
Boasts 94% light transmission.
Has finger adjustable 1/4 MOA turrets.
Only available with a 1" tube
1" tube = 58 MOA
Has the traditional threaded diopter adjustment.
Also purged with Krypton and Argon.