Ease of ordering, lower priced mattress than anywhere, and best of all the amazing sleep I am getting in spite of my arthritis.  The mattress was firmer than I expected, and yet you sink into it and don't feel any pressure points.  You sink just enough so that even if you are close to the edge of the bed, you don't feel like you are going to fall off.  For the first time since my brain injury, we don't have to sleep with my side of the bed pushed up against the wall.