Bought a couple of months ago to replace a past it spring mattress. The Dormeo mattress arrived rolled, vaccum packed  and boxed. Even though I am disabled it was easy to move upstairs and unbox. The mattress took about 12 hours to fully expand and there was no 'new' odour at all. This mattress is very comfortable even for my 21 stone. It is very supportive and I no longer wake up with various pains from an uncomfortable sleep. 
I only gave 4* as in the past I had a VERY expensive mattress which was definately 5*.
My only 'gripe' with the Dormeo mattress is how difficult it is to move across it if you are on the mattress. A thin topping layer of padding would resolve this. Apart from this I am very happy with the mattress and would recommend it to anyone. You will not regret buying it.