Hi EHLOU,
The choice between latex and memory foam would be based strictly on personal preference. You can see a comparison here but all comparisons between different materials have very subjective elements to them and I would strongly urge you to test both in person to make sure you are familiar with both materials and how they generally compare. Even though there is a wide range of different types and firmness levels of both memory foam and latex … they are very different from each other and each person can have very different preferences.
In strict durability terms … latex would be a more durable foam than memory foam but durability is also relative to each person and a mattress that lasts forever but isn’t suitable for someone in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) would have little value for that person. Post #4 here has more about the many factors involved in the durability or longevity of a mattress.
In terms of overall “material value” … you will generally find that all the mattresses made by the same manufacturer are in the same value range based on the cost of the materials (with higher priced mattresses often having a slightly higher margin) but of course value has many different components that are also relative to each person’s criteria and what I call their “personal value equation”.
Phoenix