I have read several post regarding the Select Comfort Sleep number beds and some of you refer to them as feeling like you are sleeping "downhill". What exactly do you mean? Does it feel like you are in a hole or rolling towards the middle or head or feet slanted above the other??? We are thinking about getting one and want to clarify all the negatives first. Also, we currently have a regular queen bed and are concerned about the sleep area on the sleep number queen bed being too small. Any info is appreciated. Thanks!