Hi SBLWhite,
Paramount (Nature’s Spa) and European Sleep Works both make a range of mattresses and the manufacturer of a mattress is not as important as the specifics of the mattresses you are comparing and the design and materials inside them. If you can provide the specifics of the layers and components of each specific mattress you are looking at and comparing I’d be happy to make some comments about the materials and components in each of them.
It would also be helpful to know the results of your mattress testing experience on each of them in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) because of course this along with the quality of the materials are the most important parts of a mattress purchase.
You can read a little more about Paramount in post #2 here and the posts it links to.
European Sleep Works used to carry Berkeley Ergonomics mattresses but they are now manufacturing their own (see post #4 here). They are making some good quality/value mattresses and are very transparent and knowledgeable about the materials they use and mattress design as well as “fitting” their mattresses to the needs and preferences of their customers.
Phoenix