About three months ago I got an iPad Mini. For the first two months of that time I mostly used it in an office setting (i.e. bright overhead lights). However, a few weeks ago I started using it at home for reading ebooks. Once I started doing so I noticed that when held in portrait mode there is a yellowish oval discoloration that runs from just above the home button to just below the middle of the screen. For apps and basic use this hardly noticeable and I could live with it, but when used as an ereader it is quite distracting. I was thinking of making a Genius Bar appointment to see if I could get it swapped out. I understand the new unit would be a referb, which is fine theoretically. Here is my question... Assuming Apple would swap it out, what can I expect from a referb? Are they simply units somebody returned which are then wiped and re-package or do they undergo some sort of QC check?