We went a couple of months ago to OriginalMattress F actory on highway 27 and got one of their medium (not too firm, not too soft) rated at a 56 on their scale as I recall. Heavy duty springs. A tad too firm so my wife got a topper (link below). I love it, she does too (and that's what mostly counts anyway). I have bad back issues and this has helped tremendously. Good luck, mattresses are a tough topic.
Amazon.com