As long as it is "factory refurbished" there should be no worries. They are usually packaged as new or like-new condition with full warranty should anything go wrong. My previous EF 70-300 IS f/4-5.6 was refurbished and you could not tell if it was or not. Worked flawlessy if not a little loud with the older IS version. Only tell-tale sign was the sticker that stated it was refurbished.