There are two versions of the 18-200VR. The main difference is the zoom lock on the later model, and I think it's significant. The refurb is probably the later model with zoom lock. The used one might be either.
I would think that the refurb may have a slightly better warranty: Nikon probably warranties it for 90 days, whereas the used one has no Nikon warranty at all. (However, B&H stands behind it, so compare B&H's used warranty to Nikon's 90-day refurb warranty.)
_____ Brian... a bicoastal Nikonian and Team Member
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I have found that some of my best lenses have been ones that have been sent in for repair. At first glance, it would seem that you are pending money on a "problem" lens - but I have found it to be the opposite. When a new lens comes off a production line, it is "within spec", and samples are taken from a few lenses to insure that the production is correct. When a lens in sent for repair, a technician goes over the lens individually, and ensures that everything on that particular lens is "within spec." YMMV.