No, it's not real accurate, but as good as a poll can get on a forum that has fans of various laptop brands.
One example of the poll being off is litehedded voted he had a dead pixel, but doesn't own an 8790, he has a 5680. MarkS voted he has a dead pixel but doesn't even appear to own a Sager as he's never even posted in the Sager section, only in the Dell section about the XPS. I didn't go through all the voters but there could be more and some invalid votes on either side of the poll. This is why any polls such as this and "rate your experience" are not going to be completely accurate unless we made everyone register with their order numbers. As long as you keep that in mind, the polls are fine and you can take them for what they're worth.
Every laptop demo model I've ever bought (and currently have) of all laptop brands have never had a dead or stuck pixel believe it or not (and I have a ton of laptops lol). But wouldn't you know it, I recently bought my first external LCD for personal use (secondary display)... a CTX 19" LCD and it has a stuck blue pixel =).