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I don't have a FX6 scope, but it'd be fair to assume the glass on the VX5 will have far better resolution.
The VX5 being a much much newer design and better coatings.

The VX5hd and similar scopes...

For the same price, probably yes.
A non magnifying scope will be easier to build and have a lot less lenses inside, so should offer better glass than an equivalently priced magnified scope.

That...