I would think the main issue would be with the warranty. Apple warrants their machines and has the company to back it up. Other vendors who may refurb a machine don't have a warranty like Apple's. Once upon a time I worked in computer sales and specialised in Apple machines. We would often refurbish Apple machines and would give an in house warranty of 90 days (more if you bought our extended warranty). Apple refurbished has a full year warranty and the ability to add in Apple Care. I've bought vendor refurbished machines and they have worked just fine for me, but my preferences lean more toward an official Apple refurb.