I purchased Serta Mattresses from shopnbc. Received them in October 2010. I advised shopnbc of mattresses were defective; One side is firm other side is so soft you sink in when sitting down, there is a hump in the middle felt when laying down. All brand sheets purchased for Cal-King mattresses don't fit, purchased different types and all fit too big. Serta did an inspection and denied replacement. He just measured, lifted mattresses and and pushed with his hands. I advised the inspector to sit or lay on it and he did not. I only wanted a... read full review »