I've slept on this mattress for a couple weeks now and I can finally state this is the most comfortable mattress I've ever owned. The Serta Perfect Sleeper Radian Rest is a thick mattress, at 14" thick. While being nice and thick, it is firm enough for my needs, being a heavier back sleeper. The mattress manages to be firm all the way to the edge which is great. It doesn't sleep hot at all. Highly recommended.