Hi KimRet,
The testing that was done by Mountaintop Foam which makes both of them indicates that they are very comparable in terms of durability but the natural latex would have different properties than the synthetic and would be more resilient, denser, and would be more āsupportiveā because it has a higher compression modulus (the rate that a foam material becomes firmer as you compress it more deeply). The natural latex would also be more desirable for those that prefer more natural materials in their mattress but itās essentially a budget and preference choice.
There is more about the different types and blends of latex in post #6 here.
Phoenix