I first had this on a bed of slats in an Ikea bed frame. It was just okay. It was firm enough but didn't feel very study. Then I got a regular box spring mattress (by chance, and for free!) and put it underneath this foam one, and I've loved it since. It's the perfect combination of cushiony and firm. Much better then a regular mattress alone. It did have a foul odor when I first took it out of the package. I left it out on the tarp it came wrapped in, to expand and air out for about 2 days before I slept on it. The smell was pretty much gone by then. Bonus feature: I've also noticed that it's stain-resistant! I don't know if that's a listed feature, but it doesn't seem to absorb liquids at the same rate as a regular mattress. Which is great if you're young and reckless like I am.