I had the 8.4 and just returned it. I also had the greenish-blue tint when the screen was even just slightly tilted. More noticeable indoors with brightness set to below 40%. If I had the tablet flat on the table and walked across the room, I could see it too - screen only looked good if looking at it directly in front of you. As others have said, I think it's probably due to some coating on the screen, which explains why it would be more noticeable with the screen brightness set lower.
I've checked out a few display models at stores, they all basically look the same, though some were slightly worse than others. That being said, the 10.5" ones I saw don't seem to have this problem... if they do, it's definitely not as noticeable. Not sure if it's just an optical illusion or what, but the 10.5's look OK. I'm going to go buy the 10.5 one today, mainly for the size. I'll post again if there are any tints on the screen.