Hi 70’sgirl,
Your Nature’s Rest mattress has certainly lasted you for a very long time 
This mattress isn’t “organic” and I would keep in mind that the Talalay layers inside it are blended latex which are about 30% natural and 70% synthetic latex (although this is a high quality material). It’s also very possible that any organic cotton in the cover is also blended with other non organic or synthetic fibers as well and while organic wool isn’t necessarily better quality than non organic wool … if an organic certification is important to you then I would check to make sure that both the cotton and the wool was certified organic as well. There is more about organic certifications in post #3 here.
You can read more about the Dormia / Classic Sleep bankruptcies and their purchase by their supplier and their change into Classic Brands in this article and a more detailed history yet in this article.
A forum search on Classic Brands (you can just click the link) will also bring up more comments and feedback about them as well.
Their factory in China currently manufactures mattresses under several different names and makes private label mattresses as well.
There is also more about the most important parts of the “value” of a mattress purchase in post #13 here that can help you make more meaningful quality/value comparisons between mattresses.
As you can see … PPP (Posture and alignment, Pressure relief, and Personal preferences) is the most important part of the “value” of any mattress purchase but this will be unique to each person because a mattress that is “perfect” for one person may be completely unsuitable for someone else to sleep on.
While I can’t speak to whether any mattress will be a good “match” for someone else in terms of PPP because their own personal testing and experience is the only way to know this … outside of PPP a mattress is only as good as its construction and the quality and durability of the materials inside it regardless of the name of the manufacturer on the label so I would focus more on the materials in a mattress than on the name of the manufacturer that makes it so you can make sure that there are no lower quality materials or “weak links” in the mattress.
Brand shopping can also be among the most risky ways to choose a mattress because all manufacturers have access to the same or similar components and materials and most of the most heavily advertised and most commonly available brands that you would recognize are the ones I would avoid anyway (see the guidelines here) and many of the better manufacturers are smaller and are only available locally or regionally. The name of the manufacturer on the label also won’t tell you anything about whether a specific mattress is suitable for you in terms of PPP or whether there are any lower quality materials or weak links in the design. There is more about the risks of brand shopping in post #5 here and post #12 here).
Having said all that … if the description of the mattress you were given is correct (and you can check the law label on the mattress to make sure that all the materials in the mattress are latex and that there is no polyurethane foam in the mattress) … Then all the materials in the mattress are good quality and durable materials and there would be no obvious weak links in the mattress so if your careful testing has confirmed that it’s a good match for you in terms of PPP and it also compares well to other similar mattresses that are available to you based on all the parts of your personal value equation that are important to you then it would certainly be worth considering as one of your finalists.
Phoenix