Hi Thaih,
Plushbeds uses good quality materials in their mattresses and are also transparent about what they use in each mattress and I would consider them to be a “better than average” choice compared to most mainstream manufacturers. A forum search on Plushbeds (you can just click the link) will bring up many more comments and feedback about them.
When you can’t test a mattress in person then the best source of guidance about which mattress may be best for you would be a more detailed conversation with the manufacturer who will know more about “matching” their mattresses to different body types, sleeping positions, and preferences than anyone else (see mattress firmness/comfort levels in post #2 here).
The first thing I would suggest to narrow down your choices is to decide whether you prefer sleeping on latex or on memory foam. Post #2 here has more information about how they compare but your own personal testing and experience is really the best way to know which one you tend to prefer.
The next thing I would suggest it to narrow your choices at Plushbeds to one finalist and then once you have also decided on your other finalists that you are considering at other manufacturers and are choosing between “good and good” then it’s time to make a final choice between them (see post #2 here about final choices). The tutorial post includes two links to lists of some of the better online memory foam and latex retailers and manufacturers I’m aware of.
Phoenix