Hi EcoMom,
I think any of the choices you are looking at would be a good choice for a crib mattress and I would personally consider any one of them to be a good quality and suitable purchase.
Some of them have more than one crib mattress option but comparing the Naturalmat Latex Mat, the Greenbuds Magnolia Deluxe (which is 1" thicker and a little more costly than the Primrose Deluxe but is otherwise similar), the Obasan Terra Nova II, and the SleepEZ Natural Latex crib mattress …
All of them have an organic cotton cover with either natural eco wool (SleepEZ) or organic wool (Obasan, Greenbuds, Naturalmat) quilted to an organic cotton cover (SleepEZ and Obasan and Greenbuds) or as an actual layer under the cotton cover (Naturalmat) which can add to the breathability and provide good temperature and moisture regulation to the sleeping surface.
Two of them (Greenbuds on one side and Naturalmat on both sides) have coir underneath the wool which can add additional ventilation in the deeper layers as well but this may not be as important with the wool and cotton in the layers above them. The coir in Greenbuds is natural and in the Naturalmat is certified organic.
Three of them (Greenbuds and Obasan and Naturalmat) have a removable cover which can be helpful with cleaning or airing out in the case of more serious accidents (although a good protector would prevent this and would be an important part of a crib mattress purchase). Two of them have a cover that can be washed either by hand (Greenbuds) or in a machine (Naturalmat).
Three of them (SleepEZ and Obasan and Naturalmat) are two sided with the same firmness on each side while one of them (Greenbuds) is two sided with a different firmness on each side. Having a different firmness level on each side provides the option of having a firmer side when your baby is younger and a slightly softer side when they are a little older but all of these mattresses are an appropriate firmness for a baby or toddler IMO. Having a mattress that is the same on both sides means you can flip it without changing the feel or firmness of the sleeping surface which can help even out the compression in the wool and add to longevity but all of these mattresses would be a durable choice anyway.
SleepEZ and Greenbuds and Naturalmat use 100% natural latex while I believe Obasan uses organic latex (although it doesn’t say so on their site). All of these are high quality materials that are also very suitable for infants in firmer versions. There is more about organic latex vs 100% natural latex in post #6 here but outside of the actual certification they are functionally the same and are both “safe” materials with the same certification for harmful substances and VOC’s. There is also more about organic certifications in post #2 here.
All of them are a suitable thickness (6" or less) and size so there wouldn’t be any gaps in between the crib and the mattress and wouldn’t be too thick for a crib.
All of them would be durable choices that should easily outlast the length of time your child will be using them.
I’m not sure which reviews you were reading or the issues that they were mentioning but I would take all mattress reviews with a big grain of salt (either positive or negative) because they are usually written shortly after a purchase by consumers with limited knowledge about mattresses and the materials inside them and often contain comments that are only partly accurate or relevant to someone else or which are sometimes completely inaccurate and irrelevant so they can be more misleading than helpful (outside of comments about the business itself rather than the mattress). There is more about reviews in post #13 here.
I’m also not sure what you are referring to here but if you mean fumigation then this would only apply to mattresses that are shipped on untreated wooden pallets which would be very unusual and I don’t believe would apply to any of the mattresses you are considering (see post #2 here).
In terms of “value” all of them are a fair price but outside of some of the pros and cons earlier in this post … I would probably give the edge in terms of “commodity value” to SleepEZ which contains more latex than the others and is a lower price.
Phoenix