It does seem Amazon is using a lower quality display in new Kindle's, so you want the best looking screen maybe better to go with Kindle Keyboard, Nook STR or new Sony-T1.
From
Tom's hardware review:
"We called up E Ink Corporation to ask if this was a batch-related issue, and was told that this is most likely due to Amazon choosing a particular grade of display panels. So, while the new Kindle comes at a lower price, the company is probably cutting its costs as well by using a slightly cheaper display."