We have had this mattress for 3 years. It was wonderful at first, but after about 1 year, it began to sink in the middle. We compare our bed to sleeping in a bowl. we are both in out early 30's and very active people. However, we wake up with stiff backs and aches all over. We recently stayed in a hotel and realized the difference when we woke up. That is when we started trying to take the company up on the warranty. It has a 10 yr warranty, but the company is making it very difficult (as this is "normal" wear). We are still waiting for the final word, but it seems as if they...review »