Purchased a king pillow top to replace our "bed in a box" foam mattress. We needed more support than the "bed in a box" can provide, so we transitioned to a traditional spring mattress. After just one night, it was so much cooler, more comfortable and more supportive than the "bed in a box". While it's nice for a mattress to conform to your body, it also freezes you in place as you sink into the bed; with the Sealy bed, I feel like I can easily change positions and get the same medium support I need. I've noticed that my pillow is more comfortable too with the spring mattress; it seems like my body is maybe better aligned throughout the night. I had no idea how hot the "bed in a box" bed made me... I usually sweat during the night, but with the spring mattress + box springs, it's so much cooler. It seems easier to maintain a steady temperature throughout the night, so it's all around more comfortable. If you're transitioning from a "bed in a box" foam mattress to a firmer, more supportive mattress, I would recommend sticking with soft or medium firmness. Unless you're heavy/tall, your body will immediately benefit from the firmer support of medium, without potentially waking up stiff if you select the firm support level. The pillowtop on the medium could be a little thicker/plusher; maybe my only criticism. But again - I hate sinking into a bed, and I definitely do not with this. Highly recommend this bed!