Mine arrived with one small colour bloom which disappeared after a day or two of use. The screen was otherwise flawless, and months later I'm still perfectly satisfied with it and consider it the best reader I've ever bought.
My ex also got one with no problems.
My mother's arrived with one bright pixel, but it's in the margins and didn't bother her. I could see a colour bloom, but she couldn't see it -- my colour perception is definitely above average, so I'm not surprised it looks normal to her. It also seems to have faded a bit with time, though it hasn't disappeared completely like the one on mine did.
I think it very likely your 10-year-old would love it.
I'd have been thrilled if this was available when I was 10. (I had to make do with the torch and book under the bedcovers thing.)