I actually look forward to reading all the positive user reviews, but yes, when you manufacture millions of iPads, defects will Occur. Threads are just another avenue for members to discuss their experiences, good or bad.
Pretty much every iOS device I get has had dirt under the screen. On one the screen actually had a pretty big scratch on it. I always send them back for replacements. Once it took three shipments before I got one without dirt under the screen.