The biggest 'risk' would be that there was a need for refurbishment to begin with. Never a good sign.
Open box or display models are one thing (functional, just used for display etc), but refurbished means there was either a problem, or perceived problem* at some point.
In addition, warranty on refurbished items are usually much shorter than their retail counterpart (something like 90 days via 12 months etc) - so if there's a future issue ,you might be SOL.
Sometimes items are returned open, for a variety of reasons & sold as refurbished etc - but there's no guarantees.
Unless (and it's very rare) the reason for refurbishment is stated and you're satisfied**, I'd stay away - unless it's a significant markdown you could risk...