Very nice!! They list it as a 2-3 in firmness.  I would give it a good 4 or 5.  It is soft, with firmness underneath.  I can feel it mold to me when I lay on my back.  I have very curvy hips, and when I lay on my side, I don't feel like it mold or moves quite enough (otherwise, it would be a 5). You must need an ultra plush for that. It popped up quickly. I didn't notice any odor. The only other downside is that it doesn't really conform to our adjustable bed frame.  When I put the frame in TV position, the pattress sits about 5 inches above the frame in the curve.  It does go down when I sit in the bed, but will pop back up when I leave, making the mattress "walk"around a lot. This is more what I would expect on a softer "medium" side.  We started with something else, and I am glad we made the switch.  The 100 day guarantee with Wayfair is great.  They made it so easy to switch! Thanks, Wayfair!