Hi jay55,
It would depend on several factors including the process used to manufacture the latex (Dunlop or Talalay) and is not just a “better / worse” comparison between synthetic and natural. You can read more about the different types of latex and comparisons between them in post #6 here and in post #6 here and a comparison between the aging characteristics of NR (natural rubber) and SBR (synthetic rubber) in post #2 here.
You can also read about the many factors involved in the relative durability of different mattress designs and materials in post #4 here and the posts it links to.
As you will see … these are complex questions and it’s usually best to avoid black and white comparisons which are usually not very accurate and can also be misleading (although they are very common in the information available on the internet).
Phoenix