It plumped up to full size in a matter of minutes, with no weird smell. I can't rave enough about the comfort. I bought this to replace my goose down mattress topper, which tends to bunch up in spots no matter how well it is box-stitched. The memory foam is always even and always luxuriously comfortable!The holes to keep it from getting to hot must work because even with soft flannel sheets I still stay cool and I live in South Florida!