There was absolutely no smell out of the box and didn't take long to expand. It's super comfortable. There's a bit of a sinking feeling on this one, but it's barely noticeable, a thicker topper would definitely have been too much. Seems bigger than described, it's almost wider than my queen mattress which measures bigger that the topper measurements listed. I was worried it would be too warm, but so far haven't noticed a difference in temperature when sleeping on it.