How would you rate Purple Mattress's mattresses for bad backs?

Tuck.com's review says, this about Purple Mattress mattresses: "Highly conforming, reducing pain and providing great pressure relief"

Sleepopolis included Purple Mattress in their article "Best Mattresses for Back Pain" and said, "The Purple Mattress features a top layer of hyper elastic polymer, meaning it has a fast response time. The mattress reacts quickly to movement and all sleeping positions. This can be beneficial to those with back pain because they don’t have to wait for the mattress to contour to their body and positioning. Purple is also well known for its pressure relieving abilities. One thing to note is that heavier sleepers will feel the pressure relief of the Purple Mattress easily, while lighter sleepers may experience the polymer layer as firmer."