1st thing I want to point out is that the Title of this item says 8" but it came 10". If you read carefully in the description, it does say 10". So there, if the height is important to you, and if there¿s truly a firmness difference between 8¿ and 10¿, be aware. I let mine set for 6 hrs before use. Smell, oh yes, strong and bad, for me anyway. I only had it for 3 days and the smell is definitely fading away. So not recommend using it right away unless yours doesn't smell. Now because I thought I bought an 8" so I thought it's fully inflated after 6 hrs. It was measured at 9" at one end and unevenly 7"- 8" from the other. Next day, it mostly measured 9 - 91/2" and today all sides close to 10" evenly through out. So, what is this mean? The 1st night, it was way to firm that I feel I was floating on the bed not in a comfortable way as it's hard and cold but then it's not totally unbearable I guess because I have hope from reading others comments and prepared for it. But it crossed my mind that maybe I was too light for it (I'm 5'3" 118lbs). Almost felt my back pain was back the next morning. I do have a very comfortable 4" topper ¿ 2 1/2 memory foam + 1 1/2 polyester topper which i don't want to add to it if this is comfortable enough on its own as the height is important to me for my new bed where I don't want to ended up barely seeing my headboard. 2nd night, softer! Certainty not because I got used to it, it's because it inflated more therefore less firm. I felt I sank into it a little or maybe I gained weight overnight..:o)., that made me felt warmer. The smell was bad because I covered it with my beddings, my bad, should have listened to others let it air for 2 days. Tonight will be a new night and my new bed is arrived so if I ended up using my topper with it, I guess I can never tell how good this mattress is as my topper is so comfy and mirically took away my lower back pain from the old Ultra firm mattress. I may add a comment a month or so later if I ended up not using my topper but where can you get a queen mattress for this price anyway? Let¿s hope it won¿t turn into a marshmallow like it¿s commented.