Hello! I am considering purchasing a Note from Expansys, but I am concerned about warranty coverage in the United States. I am reading a lot of reports of AMOLED burn-in and/or 'image-persistence' problems where ghosts of various on-screen graphics are basically burned into the screen similar to issues that Plasma televisions have. Many people have said they contacted Samsung to have their screens replaced. If this ends up being an issue, what would the warranty for US users be, if any..? Thanks!