I was skeptical. I'd slept on a foam topper at a friend's house and it was comfortable, but I was afraid of being too hot in AZ. But, my mattress is getting old and my back was hurting every morning. I thought I'd try it to postpone buying a new mattress. I have a Queen, and this was easy to place on the bed. I didn't notice any smell, and it seemed to fully expand in 10 mins. I put my usual sheets on the top. I woke up with no back pain for the first time in years! It wasn't too hot, either. Added bonus: the cats love it, too!