So far this mattress is very nice (only time will tell!). Using it on a king sized platform bed with headboard and footboard (no box springs). It filled out to full form within 8 hours of removing it from the box and laying it on the wood platform. We slept on it the second night and have been sleeping on it since. I would describe it as medium to medium firm. The memory foam top gives it just the right amount of "cush" over the firm spring support. We are side and back sleepers, but then I'm also used to sleeping on the ground with a self inflating mattress in a backpacking tent - so don't rely on my to describe what may or may not be comfortable!!