I just got PW today
Haven't read in complete dark yet, but as far as I can tell I am either colour insensitive or the screen seems to be just fine. I think I have a feeling I am seeing something pinkish which I cannot define but that might be after reading about all the not so good PWs and seeing something that isn't there.
In any case, after using Kindle Keyboard for 2 years my impression is that I will never miss the page turn buttons nor the physical keyboard
And that this is a way better device than the Keyboard...