I am on my third.
The first one I bought the day they released from my local Sam's Club. It was perfect except for some mild screen lift about 2/3 of the way up the left side. I followed the directions and snugged up the screws which had no effect. The lift became worse with use/heat. I returned it.
The second one was a Sam's Club pre-order which was also perfect except for some very mild screen lift in the same place as the first one. While not nearly as bad as the first one, it did have some creaking when I pressed in that area. That bothered me so I returned it as well.
I made sure the folks at Sam's knew both of these units were defective so they didn't get put back in any sort of "open box" rotation or anything like that.
I just bought my third one on Friday from my local Office Depot (tax-free weekend). Out of the box, it was absolutely perfect. However, after some use I can now see some ever so slight screen lift at about the half-way point on the left side. It's perhaps 3-4" in length which is more than the first two, but nowhere near as high. I plan to keep this one. I also purchased the 2 year accidental damage plan since I didn't have to pay tax. The lift on this one is just barely enough to catch my nail when I slide it across. Without really good light (and eyesight), it's imperceptible.
I checked for dead pixels and light bleed on all three and had none. The only thing I don't like about this device is the washed out or over-exposed color tint. I'm hoping this can be fixed in a future update. But it isn't a deal-breaker for me.