Hi Brent743,
You certainly made a great quality choice … and congratulations on your new mattress 
The Nature’s Embrace 8" Opus is a multizoned mattress with firmer and softer sections under different parts of the body. Zoning can help to make sure that the heavier parts of the body such as the hips/pelvis are better supported by the firmer sections so they don’t sink down as far which can help to maintain better spinal alignment over the course of the night which can help prevent lower back issues. It’s probably more noticeable to you and may take a little time to get used to because your previous mattress was the opposite and was sagging in the middle.
Zoning systems can certainly be useful and well worth considering for people that have more difficulty finding a mattress with the right “balance” between comfort/pressure relief (under the shoulders especially) and support/alignment (under the hips/pelvis especially) or who have more challenging circumstances or sensitivities, body types that are more difficult to “match” to a mattress, more complex medical issues, or who have a history of having more difficulty in finding a mattress that works well for them. There is more about zoning in this article and in post #11 here and the additional posts it links to.
Phoenix