I can't seem to find any info about what hyundai's policy is on dead pixels. I was going to buy two of their L90D+ monitors but I dont want to dive into a bad product.
I think you have to check with the retailer for their policy on returns. For example, Newegg's policy is eight or more dead pixels for a return. You wouldn't normally return a product to its manufacturer, so find out from the store you're planning on getting it from.