Hi danwynn31,
There is more about the different types or “levels” of organic certifications in post #2 here but the three you mentioned are the only ones in the US that are listed on the GOTS site that have organic certifications for their manufacturing facilities rather than just the individual components or materials in their mattresses so they are the only ones that sell mattresses that are certified organic as a “complete mattress” rather than just having a certification for the materials inside the mattress.
GOLS (Global Organic Latex Standard) is only a certification for the manufacturing of organic latex cores … not for a complete mattress.
Phoenix