I have half a dozen VariX-III and VX-3 2.5-8x scopes that I've used on a number of rifles over the last 20 years or so. I've never had any problems with them except sometimes the tracking is not exactly correct when zeroing. They have held zero well once it's established. Overall I've been very happy with them. I don't have any VX-3i's in 2.5-8x although I do have one in 3.5-10x that has worked fine for me.
