So, the benefits of 100% natural are purported to be non-exposure to petroleum-based synthetic latex, which makes up, what, 60 to 70% of blended latex?  Seems prudent to avoid exposure when possible.

But looking at FAQs on this website, it states that 
"natural latex has a lot of impurities in it which is only natural, so it breaks down much sooner than the mix."

And Latex International, who appear to be producing the natural latex used by the better known dealers, state on their website that
"Wear and tear simulation testing shows blend superiority. 100% natural latex cores experience 5 to10% more mattress core height loss (i.e. body impressions) due to wear and tear than our Talalay and 2 to 3 times more loss (softening) due to repeated sitting and sleeping."  I guess if blend softening is really minor than 2-3 times that small amount may not be that great, or 2-3 times could be a huge difference.  They also don't discuss how long that core height loss takes to occur.   It also appears the 100% natural product has only been offered by LI for about 2 years.

Flobeds warranties both natural and blended latex for 20 years, which appears to reflect their confidence in the natural product, although I don't really know what value a pro-rated mattress warranty really has.  I would appreciate hearing from those who have or are about to purchase latex, and how they made the decision to go either way.  For those who are chemically sensitive it seems a no-brainer to go natural, but for others, why choose the more expensive choice with shorter longevity and resiliency?