It feels like this mattress never fully inflated. When I sit on the edge of the bed (or even when laying) it's like you sink way down. I would say this is not a medium firmness - more like a plush. Also noticed that this mattress does not have any cooling effect - in fact - quite the opposite. I wake up feeling almost damp (I am not typically a sweaty sleeper), but this mattress definitely makes me very hot.