If they say "refurbished" it more than likely means there was a previous owner who returned it as faulty, in which case it was sent away for repairs.
Ex-display models are sold as "re-mastered" i.e. sold in original state and packaging apart from having been on display.
In either case you should be guaranteed the standard 1 year manufacturers warranty. In both cases, you should look for a discount off the price of a pristine laptop -> 10-30% is normal.