I bought this mattress because I wanted a firm mattress. It is very firm. However, even from the start there is a depression right in the middle of the mattress where hips go. Thankfully it doesn't extend the entire width. So I can shift a bit to avoid it. Maybe it is a manufacturing defect or gap between coils. I am not sure. I hope the quality control gets improved. People have high expectations from you. Please don't let them down. 

I am going to keep it to avoid wastage.