While the product is great and I was really excited to try it, it seems I am the 10% for whom the mattress didn't work. It's been a month of usage and I haven't spent a single night comfortable. In fact I've developed severe upper back, shoulder, and neck pain sleeping on it. I've finally switched back to my old hard mattresses and the pain is getting better. So if you have back issues, this probably isn't the best mattress. I am sad that I have to return it!