This is a fantastic mattress.  I was looking for something very firm, but something that would also allow me to sleep in any position.  This mattress fits the bill.  It supports my back when I sleep on my back or stomach, but also accommodates my hips me when I sleep on my side.  The firmness rating for this mattress is listed as a 9 out of 10, but I would rate it more like an 8 to 8 1/2 out of 10; comfortably firm, but not overly firm.  If you are looking for something that is as firm as a board, I'm not sure you'd be happy with this product.  Otherwise, you'll love it.