we were a bit taken aback when we realized that it was a mattress "in a box". 
but after the first night we realized that we had purchased a very high quality bed. I am 6'2, 184lbs with a L5-S1 injury and now I wake up with no low back pain. My wife is 5'4, 145 lbs and always had hip pain in the morning. With the new mattress, she has not had any pain at all!!
So yes it is worth buy that mattress.