Hi cheesepuff,
There are really only two ways to make the kind of comparisons you are looking to make. The first is by price which would mean you would need to get all the specs of the mattress you purchased (including the quality/density of the polyfoam layers) and then look for a mattress that is close to identical to compare it to (I don’t have a list of mattresses based on specific designs) but this may take you many many hours and the odds are good that you won’t find a similar mattress anyway and in most cases you won’t be able to find out the quality specs of the mattresses you want to compare it to so the hours would be wasted anyway (most major manufacturers don’t disclose the quality of the materials they use in their mattresses so there is no way to really make meaningful comparisons).
The second way is to compare by quality. This means you could look at major brand mattresses that sell in the same price range as yours and then compare the quality of the materials as best you can (again most major manufacturers don’t disclose this but you can assume in most cases that any polyfoam is in a lower quality/density range).
The first way you would find your mattress has a lower price than similar mattresses (to the degree that you can compare them) and the second way you would find your mattress has better quality materials than major brands that have a similar price. Of course you would need to compare mattresses of the same size (you didn’t mention the size you purchased).
In addition to that of course there are many other parts of the “value” of a mattress purchase that you would need to factor in as well (such as the value of customizing a design to your specific criteria or the ability to make any changes you may need to) that may be part of the objective, subjective, and intangible factors that are important parts of your personal value equation.
Whichever way you decide to make value comparisons you will find you did very well.
Congratulations on your new mattress 
Phoenix