Hi AT,
Thanks for finding out and listing the specs of the mattresses you are considering.
Both of these mattresses use good quality materials that meet the quality/durability guidelines here and there are there are no lower quality materials or weak links that would affect the durability or useful life of the mattress in either of them (unless you are in a much higher weight range than average in which case the latex support core in the Nirvana could make a bigger difference compared to the 1.8 lb polyfoam in the Utopia in terms of durability) .
They both appear to be similar in terms of firmness based on the top latex comfort layers and if anything the ILD specs seem to indicate that the latex core in the Nirvana may be firmer than the polyfoam support core in the Utopia but the latex in the support core of the Nirvana would be more “point elastic” and contouring than the polyfoam support core in the Nirvana so it can “feel” softer than polyfoam because of the properties of the latex even though it actually isn’t when it’s physically tested for firmness. There is more about the pros and cons of a latex hybrid vs an all latex mattress in post #2 here.
If you are confident that either or both of these mattresses are a good match for you in terms of PPP and they also compare well to any other finalists you are looking at based on all the parts of your personal value equation that are important to you then they would certainly be well worth considering as a purchase.
ADDED: see my comments in post #24 here about the updated and edited specs and I would consider the 2.5" of polyfoam in the top layers to be a weak link in terms of the durability and useful life of the mattress.
If you are also considering the Nirvana mattress then given the misinformation you were originally provided I would also make sure that the mattress is really 11" thick to make sure that there are no missing layers of lower quality materials in the upper layers of this mattress either that would affect the durability and useful life of the mattress.
Phoenix