I purchased this mattress a few months ago. I selected firm, because over time all mattresses get softer, so I believe you want to start as firm as possible for longevity. 

I'm very surprised with this mattress.  It's my first box-bed, so I expected less. To my surprise,  the mattress is substantial,  you'd never know it came out of a small box. It's more comfortable than a bed I paid 4x more for (in my guest room).
I've invited many visitors to lay on my bed (yep im a weirdo), and have converted many of my friends into owners. I write this review tonight, because a friend just messaged me forfor brand name and retailer..

No mattress lasts forever, when this one wears out, it will be replaced with this same brand.