OK. Have you been able to see passive 3D (Vizio or LG LED are passive, most others are active) in any store demos without having this problem? The reason I ask is that there is a significant percentage of people that just can't view 3D. If you've seen it in demos and it hasn't had this defect then you are not one of these people and have a problem with your set or it's configuration/compatibility with your FIOS box. I think Vizios have a provision for manually selecting the proper 3D format for the incoming signal--side by side, top/bottom, etc. Try changing these settings if you can find them (might have to check the owner's manual). I'm not sure about FIOS but DirecTV uses the side-by-side format for it's 3D (Blu Ray uses something called "frame packing".)
There also should be a setting for the degree of 3D effect displayed by the set which can, if set wrong, produce a lot of ghosting but usually not to the degree you're experiencing.
Finally, it might be a good idea to get a 3D Blu Ray player and a recent release 3D disc and see if the problem still occurs. If you're intending to stick with 3D even if you return the Vizio you'll want a 3D bd player anyway so it's not a waste of money.
I have an LG passive set, PS3, and DirecTV and the 3D from Blu Ray is significantly better than that on DirecTV.