If one iPad is bent and that affects your decision to purchase one, I completely understand. But basing your decision solely off biased statistics representing a very small subset of Apple users seems extremely foolish to me. People come to forums for two reasons, because they have a problem or a complaint, or they're an enthusiast. This 21% you allege ignores the millions of people who don't come to the internet to exclaim how great their product is. Not to mention, the majority of forum members who have no issues at all, are likely to not vote in the poll in the first.
TLDR: Any poll posted on this site will not be representative of a larger experience and should not be used for anything other than anecdotal information.