Okay, went thru two, a week 47, then 48 and now this third one a 48 as well. For the record, no dead pixels on any of them. The first two had noticeble yellowing, lots of it. This one might have just a tiny touch in one corner, but it's at the point where I can't tell if my eyes are playing tricks on me or not. So I'm going to hang with it, play with it and if it gets worse take it to Apple later this year. The machines are so freaking amazing though, that it was worth the hassle to find a good one. I'm sure Apple's supplier for their LED screens are all hanging from shower curtain rods right about now... imagine the returns.