I honestly can't say I've slept on this mattress, but I can vouch for my 9-month old granddaughter, who seems very comfortable and content to nap in her pack 'n play on this mattress. To paraphrase a favorite story, "it's not too hard, it's not too soft, it's juuuust right." The measurements given were accurate, and it was a nice, tight fit in the pack 'n play, leaving no gaps at the perimeter, nor did it bow up in the middle from being too large. The outside covering was a bit stiff, but covering it with a cushy mattress pad and soft cotton sheet will make for a cozy, cuddly naptime space.