I bought this mattress for my 4 year old's new twin bed (an upgrade from her crib.) The mattress is very firm, which is perfect for her because it feels similar to her crib mattress. The whole family, in fact, prefers her bed to all others in the house now! We've never used a foam mattress before so I didn't know what to expect but this one is so comfortable my husband and I are considering purchasing one for ourselves. We gave it about 4 days to unfurl in the guest room before putting it to use. I initially noticed a slight smell but that could have been from the plastic it was wrapped in; now after two weeks of use there's no smell whatsoever.