Did quite bit of research before buying crib mattress. Debated between foam and coil based ones, but settled on a coil mattress because of concerns over polyurethane foam which is in 99% of foam based crib mattresses and breathability of foam. Didn't want to go paranoid and shelve out $500 on a naturepedic crib mattress, so decided to buy something which has as few toxic chemicals as possible.
The latex used in the mattress is natural (according to LA Baby). The fire retardant is boric acid which is not great, but way better than toxic chemicals used in most mattresses. The mattress is appropriately firm, true to dimensions and fits great with the babyletto hudson crib. No smell after opening the packaging which is reassuring. Very satisfied so far.