>First one is N70968000xxxxx, the second N70969000xxxxx
Same here. I got a replacement KA1 after the orginal had green blotches when natural light was on. QC is definitely an issue, as you can see from the picture.
http://i.imgur.com/D8VGoRs.jpg
8000 batch on the right, 9000 batch on the left. I kept the "warm white" version and returned the "cool white" version, mainly because the green blotches in the original 8000 batch KA1 were very distracting and the replacement is much more even (although not perfect, this one veers towards red blotches rather than green)
Both have slightly misplaced front screens with minor gaps. The replacement also has a somewhat loose back plate, and there were a few scratches on the finish when I unboxed it (not an issue for me).
Battery life is about the same in both, they both drop about 5-10% an hour when reading with backlight on.
I have left the wifi on in the replacement and haven't experienced the nocturnal battery drain issue yet.