Hi Tomcat,
Dreamfoam is a manufacturer (not a mattress) and like all manufacturers they make a wide range of mattresses in different budget ranges that use lower or higher quality materials relative to each other. They are a member here which means that I believe they compete well with the best in the industry in terms of quality, value, and service and they are certainly one of the manufacturers I would recommend yes. Of course there are many factors involved in a mattress purchase so which of their mattresses would be most suitable or would have the best “value” for you would depend on the parts of your personal value equation that are most important to you.
There are many factors that affect the durability of a mattress and this would have more to do with the suitability of a specific mattress and the materials inside it than with memory foam in general. All materials have more and less durable versions. Lower density memory foam (such as 4 lbs) can be a preference for many people because they can sometimes be softer, faster responding, or more breathable than higher density memory foams but they also won’t be as durable as higher density memory foams so for some that are in a higher weight range a higher density may be a better choice. The suitability of the materials in a specific mattress in terms of PPP and durability relative to the circumstances or preferences of a specific person is always more important than who makes the mattress and a mattress that is durable for one person may not be as durable for another. There is more about the factors that can affect the durability and the useful life of a mattress relative to each person in post #4 here and there is more about the differences between different types of memory foam and why some people would prefer one type over another in post #9 here and post #8 here.
If someone who is in a higher weight range is sleeping on thick layers of 4 lb or lower memory foam or there are weak links in a mattress relative to their specific circumstances then in many cases it could lead to issues that affect the useful life of a mattress (regardless of the manufacturer).
South Georgia is a little to big an area to look but if you can give me your city or zip code I’d be happy to link you to the forum list that is closest to you and includes the better options I’m aware of in your area.
Phoenix