I have a not very nice black dotted line that runs across the full length of my Nexus 7 screen about half inch in. It's not that bad because it's only half inch in from the edge of screen but it clearly shouldn't be there. I'm therefore going to return it for a replacement. I would urge people buying from a high street store to turn on and check there product while in store as I have heard of other people having screen issues and it would be worth checking your tablet out or you might find yourself returning to the store for a replacement.
Hi guys, I had pixel failure on my screen so I took my Nexus 7 back to the store for an exchange with no problems. I ask to turn on my replacement Nexus to check for any obvious screen issues and I found no problems:-). I found out at the store that Google have no warranty terms apart from the standard one year so it will be a straight exchange for a replacement Nexus 7 within one year after purchase.
You are all welcome to add to my post if you have had any screen issues like myself.