My wife and I bought a new mattress here. We told the salesman that we were getting rid of our old mattress because a hump formed between where we sleep and sleeping on a sideways slope every night was causing back problems for me. The sales man was friendly and low pressure. He helped us pick out a mid range mattress that he said would not have the same problem. Unfortunately the new mattress is doing the same exact thing. I am now sleeping on the couch regularly because it is more comfortable. We still have not even paid off the mattress and we will be replacing it.
To put a long story short, do your own research. Don't trust the sales people here. They are not knowledgeable in the products. It is likely that they are trained based on vendor marketing information, not real world experience.