Hi Bessi,
Welcome … and I’m glad you found us “in time” 
I switched your post and my reply to a new topic with a more specific title so it wasn’t in a more “generic” topic that will get mixed up with other replies and would be more helpful for others that are making the same choice.
I’m not sure which Naturepedic mattress or which Flobeds mattress you are considering or the criteria that are most important to you but both of these use high quality materials and neither one has any weak links in their materials or design. While I can’t tell you which one to choose … post #13 here and the posts it links to has more information about the most important parts of the “value” of a mattress purchase that can help you with “how” to compare them. I’m also assuming that you’ve read the tutorial post as well which has all the basic information, steps, and guidelines that can help you make the best possible choices.
As you probably also know … Flobeds is one of the members of this site which means that I think very highly of them and I believe that they compete well with the best in the industry in terms of their quality, value, service, and transparency. If you are looking at their vZone mattress then they also have more options available to customize the mattress both in terms of layering and in terms of zoning than almost any other mattress I’m aware of. There is more about Flobeds vZone mattress in post #4 here.
I’m not sure if you are considering a Naturepedic from a local store or are considering an online purchase but either way the retailer or Naturepedic will be able to tell you the specific materials and components inside any of their mattresses. The latex they use in their mattresses is GOLS certified organic Dunlop. The choice between Dunlop and Talalay is about personal preference but there is more about the differences between how they “feel” in post #7 here. There is also more about the different types and blends of latex in post #6 here and more about the different types of organic certifications in post #2 here.
Many couples do well with this and it can be a particularly good choice if you have or are planning to purchase an adjustable bed where you would like to raise and lower each side independently. There is more about the pros and cons of split king mattresses in post #8 here and in this topic that may be helpful as well. For some couples having the ability to raise and lower each side independently isn’t as important as avoiding the gap in the center of two twin XL mattresses and there are also some companies (including Flobeds and Naturepedic) that can customize each side of a mattress individually for a couple that has different needs and preferences so you would have a single mattress that doesn’t have any gap in the middle.
Hopefully this has helped. I’m looking forward to finding out what you end up deciding and of course any other questions or comments you may have along the way.
Phoenix