You are getting essentially new - these have been returned and a restocking fee paid. There are very rare horror stories, but they all end with another unit being sent out straight away. These are outnumbered by the stories of the unit exceeding the listed specs! It has exactly the same guarantee as store bought goods and you can buy the AppleCare warranty for it too. You *can't* use the Student Discount or configure it .
[edit] missed the ['t] in above!
In answer to below, you get the standard 1 year warranty with all Apple Hardware, and like storebought you can extend this to 3 with AppleCare.