Bought a King size Estate Sterns and Foster mattress fro Mattress King. It was delivered and set up Friday afternoon. Installed the special mattress cover recommended by Mattress King and made the bed. I lay down on it on the side that I normally sleep (I am 6 feet tall and weigh 185 pounds). I sank down about five inches into the mattress and felt like I was laying in a trench. I was immediately concerned and commented to my wife that it was much less firm than the Sterns and Foster Queen size we had bought last year. We bought them both from the same sales person and she assured us that this King size mattress would be the same as the Queen size otherwise. I then rolled over to the middle and it was much firmer, I did not sink down. I then rolled over to the other side and it was much firmer also. My wife lay on it and she experienced the same thing. The mattress was perfect everywhere except the left side as you normally lay on it. We tried to call the sales person early Monday morning, but she it was her day off, so we called her Tuesday. She denied that this was remotely possible and asked us to send her a picture that showed that the mattress was uneven. I explained to her that it was not uneven when no one was laying on it. She said she would talk to her District Rep and get back to us. It does not sound like they are willing to warranty this defective mattress.