Hi jkmason,
The latexmattressshop site is not up to date and their main focus in on their Amazon mattresses. If you look at the description for the Enchantment you will see two completely different descriptions and I don’t know which one is correct. They do have an all latex mattress on their Amazon site here which allows you to choose the firmness of the 6" core and then add the top 3" layer of your choice which is also exchangeable. If you do choose to go with the Enchantment (which they can still make) … I would confirm the layering and construction so you are clear what you are buying.
As far as a comparison between an all latex mattress and a latex hybrid mattress … post #2 here which compares the two different types of design should be helpful in helping you decide which one best fits your “value equation”.
Phoenix