Well if the display was bad enough to be sent back originally, you should also be able to send it back if they didn't fix it. I haven't heard anyone complain however.
I have a Macbook that was delivered on Friday and everything is perfect but as I have stated on here before you have to be careful what you pay for them. There are some items that you can purchase new for another $100. In those cases why buy something that someone has sent back for some reason. If you can always check the Education store on line at the Apple site.
My refurbished, white, Santa Rosa MacBook just arrived Friday. It seems to be absolutely flawless. Trust me, I am a perfectionist, and I can't find anything wrong with it.
WHICH... you should probably utilize... because if you think about it - you are paying money up front for your applecare... why not just keep the money in your own bank/CD/investment for an extra year... its like a $10 discount!