Factory refurb's can be a good deal if the price is right. I need to differentiate between refurbs and 'B' Stock. Factory refurbs, generally, carry same warranty as new sets and are free of blemishes.
I think the thing to pay attention to with factory refurbs is the warranty. Some companies only provide for a limited (usually 90 days) warranty on refurbished product, while other companies give the same warranty as if it were a new product.
If it's something that's got a good warranty, why not?