I ordered a refurbished 27" i7 a week ago. It had a definite yellow tint, so I took it back to a local Apple store. After several debates with "geniuses", I used the test page mentioned here in the forums to prove there was a problem. They replaced the video panel, and I just got the machine back. Now I've notice that someone got finger smudges on either the video panel or the back side of the glass. 
I plan to use this mostly for light-weight digital photography; Lightroom, etc. The new panel is only the slightest bit yellow in the lower right. I can live with it I guess I'm going to take it back in for a cleaning, but part of me wants to just return it, and give it a month before I try to buy something else. Frustrating! Maybe I need to live with a slower processor and get a 1Tb Mini with a Cinema display.
I plan to use this mostly for light-weight digital photography; Lightroom, etc. The new panel is only the slightest bit yellow in the lower right. I can live with it I guess I'm going to take it back in for a cleaning, but part of me wants to just return it, and give it a month before I try to buy something else. Frustrating! Maybe I need to live with a slower processor and get a 1Tb Mini with a Cinema display.