My rationale behind a four-star rating for the NuForm 11-inch Foam Mattress has to do with an issue that does not bother me but might bother others who are contemplating a purchase. The mattress is rolled up, which means it has to be unrolled, which in turn means one has to wait until it settles into its final shape (24 to 48 hours according to the included document). Rolled up foam mattresses are obviously different than rolled up spring mattresses, and I've had the NuForm mattress for weeks now and it still isn't completely flat; at least two of the corners continue to resist. Despite this, after giving the mattress the suggested 48+ hours to flatten out, I've slept on it comfortably every night since, and ever so slowly the stubborn corners are returning to their correct flattened positions.
I purchased the NuForm to replace a California King-size water mattress, which I've had for decades. I kept the waterbed's frame and headboard and simply dropped the NuForm into the frame. Notwithstanding the remaining curled corners, it fit perfectly and settled into the frame just under an inch above the frame rails. The quilted pillow top is soft enough to let you feel a squish when you lay on it, but the squish is fleeting because the mattress itself is firm.
If you already have a frame to accommodate an 11-inch mattress, or plan to purchase a frame, I can recommend the NuForm for your consideration. If the still slightly curled up corners (that are ever so slowly flattening) bother you, well, all I can say is they don't bother me and I expect they will eventually regain their final shape. (You could, I suppose, turn the mattress upside down until it flattens.) In other words, the four-star rating is for you, not me, because I am completely satisfied with the NuForm.