I have two experiences with refurbished products:
1) Bought a refurb Kicker KX350.4. It kicked ***. No problems, nothing, great amp.
2) Bought a refurb Profile 100x2@4ohm amp, from profile, and it blew up (yes exploded) my crossover. I had to wait 2 months for a new one. Needless to say i got a full refund.
Buy from a good, reputable company, and you should be fine.