Outside of the optical differences, the VX-3 has a locking focus ring, the VX-2 does not. If you feel that's not a big deal, just see how much the reticle can move around with little effort on the VX-2.
Other than that the VX-2's are nice scopes
My focus ring on my VX-2 is rock solid... meaning, it actually takes quite a bit of force to move! I think this must have been a Leupold fix (?), as it is anything but easy to move around.
May very well have been a bad scope I had. With the ocular bell threaded out maybe 1-1/2 to 2 turns from stop, there was enough play to move it roughly 2" on a target @ 100y.